No problem, anytime is a good time to start learning the joy that is level editing. Below I have provided you with the necessary links that you'll need to start editing.

https://steamproxy.net/app/562860/discussions/0/1642045637384574237/
This is the original post made by the developers that provided the links. There is no real need for opening this, because I will provide you with the same information.

http://voidpoint.com/public/IonFury_LevelEditor_20190815.7z
This is the level editor itself. You will need to download it and extract the files to the destination where you installed Ion Fury. For most people that would be steam\steamapps\common\IonFury.

https://infosuite.duke4.net/
https://wiki.eduke32.com/wiki/Level_editing
https://furymap.lerppu.net/
These links will lead you to guides and tutorials for making level with Mapster32. Ion Fury uses a modified version of Mapster32, but there shouldn't be to many differences. To find out what is new, I would recommend checking out the third link of the section.

First make your room or area in which you want your light to be in. I only just made a small cube with some simple textures.










Now add your light source, this can be anything: A sprite, sky-like area (like a crack in the ceiling) or a solid sector-shaped light source (this is what I chose to do, but you can absolutely do anything you want).










After you're done with that, add in a sprite for the light gradient section. You can access that section by doing the following: When choosing textures, press T. This will give you a list of sections of all your textures. This is useful for when looking for specific types of textures like metal floors or stone walls, but also for light gradients.
Now press R and all the light gradients should have popped up. Now choose one that suits your light source, for the example in the picture below I went for Tile: 7660.
After selecting one, chance the size and rotation to make it fit the light source. The gradient doesn't look very good yet, but in the next step we'll change that.










Now go into 2D mode and hover over the light gradient sprite and press F8. Now on the bottom of your screen a menu should have popped up. In this menu you can find all the important information about the sprite.
Now go over to the blend option and press ENTER. Now you can change it's value. Change it to around 129 (You can play around with this, so experiment what looks best to you) and press ENTER again.










Click on the picture above to zoom in.

Now go back into 3D mode and... it seems like nothing has changed. Don't worry, this is supposed to happen, because we haven't made it transparent yet.
While hover your cursor over the sprite, press T once or twice. Now it should have changed into a proper gradient and that means you're done.
Well done!

First create the playing area (basically your level). This area/sector can be any shape or size.










Then increase the height of the ceiling and texture all the walls and the floor. After that you need to give the ceiling a specific texture (Tile: 6143 T_SKYPORTAL). This texture will act as the texture that will be replaced by the skybox later on.










After you've done this, you have to create the skybox area. This area/sector can also be any shape or size.
Do keep in mind that you don't make it too big, because the area will be enlarged automatically to a scale to 1:8 ( 1 pixel play area = 8 pixels skybox sector).










Now make a slightly smaller shape around the edges of the skybox sector (on the inside of this sector). I'll make clear why in a minute.











Now go into 3D mode and change the height of the ceiling and change it's texture to Tile: 6100. Make the ceiling parallax by pressing P.
Now lower the sector's ceiling around the edges of the skybox sector (don't forget to parallax that ceiling too) until you hit the floor. The walls are now gone and the sky now looks more realistic already.











Now add some buildings around the sector (not in the Middle!) You can decide it's size yourself since it's your skybox. You can also edit them later so don't worry. Keep in mind to scale the textures correctly, otherwise you'll see some buildings with really windows. This is something I didn't do properly in the screenshot. Ignore the S like sprite in the screenshot, it will be explained in the next step.










Now add an sectoreffector to the middel of the room. This is a sprite with the sectoreffector texture (this can be found right at the top of the texture list). Now go into 2D mode and give the sprite a lowtag of 100 (press alt + t while hovering your mouse over said sprite). This will set it to skybox "mode".
Now also give it a palette value of 0. It's 0 as standard, but if you want to make sure press alt + p while hovering your mouse over said sprite and the palette value can only be altered in 3D mode). Now the sectoreffector acts as a 360 camera.










Now do the same in the play area. Find the most center part of your map and place a sectoreffector there. Give it a lowtag of 100 and a palette value of 1 (it should have turned grey). Now the sectoreffector acts as the anchor-point for the camera.










Now go into 3D and make your play area look nice and make the ceiling parallax.











Now test your map and it should have worked. If it didn't, read the guide again closely or ask questions in the comments.










Quick tip: If you give both sky textures a palette value of 7, they become dark blue. This makes it look more like nighttime.

First find a song/track that you'd like to use for your map.

Then convert the files to one of the following formats: ogg, xm (More will be added after more testing). Keep in mind that the mp3 format will not work.

Now place your music file/track in the location where your map is stored. So the map and track will be in the same place.

Lastly, change the name of the music file/track to the exact name of your map. For example: YourMapName.map would use YourMapName.ogg.

This should have worked. If it didn't work, then feel free to ask any questions.