If you use Nexus for modding, you may encounter mods like Place Anywhere which need F4SE to be loaded.
The installation is a bit tricky, but here's how you do it:

Step 1: Download
Go to the F4SE download page [f4se.silverlock.org]. Download the Fallout 4 runtime and unzip it with 7-Zip.

Step 2: Install directory
Go to your Fallout 4 default installation folder. It's inside the Steam folder, which is dependent on your installation path. If you did not change anything, the normal path is C:\Program Files (x86)\Steam\steamapps\common\Fallout 4.

Step 3: Disable the Fallout 4 Launcher (skip if you are not launching from Steam
Move the Fallout4Launcher.exe file to antother location, like your desktop, or rename it. This step is very important, do not skip it.

Step 4: Copy the entire F4SE folder inside your Fallout4 folder
You need to copy everything from the F4SE folder to your Fallout 4 folder. Make sure to copy all files for folders, if you're asked to overwrite or replace a file, click Yes. Make a desktop shortcut for F4SE_loader.exe (if you want to launch from Steam, skip this and go drectly to Step 5)

Step 5: Installing the Steam F4SE launcher


Step 5: Allow F4SE to be launched via Steam (OPTIONAL)
Download F4SE Steam Launcher [www.nexusmods.com] and extract it (with 7-Zip).
Look inside the "F4SE Custom Steam Launcher" folder. In there is a file called "Fallout4Launcher.exe". Put it directly in your Fallout 4 folder.

Step 6: Verify the installation
Launch the game via Steam. Load any save. Then, open the console (Tilde key on US keyboards, ö on German keyboards, look here [falloutcheats.com] for a complete list)
Then, type "getf4seversion" (without quotation marks". This verifies the installation and displays the build number of the current F4SE version.

Thanks for reading my guide!

-- JKL213