Editing the mod load order in games allows for certain mods to function correctly and even allows for modders who aren't the creators of mods to edit mods with a separate mod.

Using this function allows you to choose which mod you want to take priority for editing the game e.g: my mod (Department of Diagnostics) edits the CSF sampling exam which is also edited by Bedside Examinations (Butch). This means if his mod loads after my mod then CSF sampling won't be able to be done at my department however, if my mod is loaded after his mod then his edits wont be available. The logical choice would be to load my mod second as CSF sampling is needed in my department and my mod makes CSF sampling able to be done in any department.
This can be utilised to work around conflicts and also allows the use of conflict patches to get benefits from both mods.

The mod load order is accessible in steam, the following screenshots will show you where to find it.

First click on Project Hospital in your game library and click on the cog on the right side of the screen:


Next click properties:


A menu should pop up, click on workshop:


Here you will find your load order.

Once you find the load order menu you can edit the load order by clicking on the hamburger icon and dragging the mod to the desired location in your mod load order:


Some mods have long names so the hamburger icon isn't visible, in this case the point where you can drag mods is usually where the file size is shown. you can tell where this is as the mouse pointer changes to a hand like this:


Mods are loaded from the top down in the load order starting from one, mods loaded first are overwritten by mods loaded after.

Sometimes mods are installed outside of steam workshop, in this case you can set the load order by changing the name of the mod in the addons folder. In my testing I have found that adding numbers to the beginning of mod files allows you to easier set load order however this can make it so that mods are loaded before dlc, you can change this by adding numbers to the dlc folder aswell. Locally installed mods will always load before workshop mods and they load in alphabetical order, they also don't show up in the steam load order menu.

The mod list in the bottom left corner on the main menu of Project Hospital shows the order in which mods were loaded with the top mods being loaded first, in this image you can see my mod which is locally installed is loaded before the mods in my load order on steam: