SLAnimLoader registers custom animations with SexLab. It reads information about the animations from Data\SLAnims\json\
This makes it possible to add new animations without needing to edit any mods or do any scripting. This also makes it easy to change animation tags, actor positions, sounds, mouth positions, etc.
While you can edit the JSON files manually in your favorite text editor, this isn't recommended. Hand editing these fields is tedious, and it's easy to get the syntax slightly wrong. If you have a syntax error, Skyrim will fail to load the file and won't give you any error information about what line of your file was wrong.
Therefore SLAnimLoader supports building the JSON data from source files in Data\SLAnims\source\.
Data\SLAnims\source\Example.txt contains a brief overview of the syntax of the source files. The Example.txt file itself will be automatically skipped by SLAnimGenerate, since it contains the line "is_example = True". You can remove this line if you want to play around with it in SLAnimGenerate, but there aren't any actual animation files associated with it, so no animation stages will be found. If you copy Example.txt to start building your own animation pack, be sure to remove the "is_example = True" setting.
You will generally want to group all of your animations into a single category. Pick a name for your category, and create a source file with that name. For example, Data\SLAnims\source\YourCategory.txt
Now put your *.hkx animation files into into the directory meshes\actors\characters\animations\YourCategory\. Animations for creatures should go into the appropriate creature directory (e.g. meshes\actors\draugr instead of meshes\actors\characters).
You will have one *.hkx for each stage of each actor. Your files should be named AnimName_A1_S1.hkx for the 1st actors 1st stage, AnimName_A2_S3.hkx for the 2nd actor's 3rd stage, etc.
In the YourCategory.txt source file, add a new Animation() statement for your animation. The "id" field must match the name of your animation files. e.g., put id="Foo" if your files are Foo_A1_S1.hkx, Foo_A1_S2.hkx, etc.
Run Data\SLAnims\SLAnimGenerate.pyw to process your source file. This will generate a corresponding JSON file under Data\SLAnims\json, and will also generate FNIS lists in each of your animation directories (one for each race).
Any time a FNIS list file is updated, you need to re-run GenerateFNISforModders.exe to process the list file. After you have processed all of the FNIS lists, then re-run GenerateFNISforUsers.exe.
Once this is done everything should be ready to start Skyrim and register your animations.
Once you have loaded your animation into Skyrim, you may notice that the actor positions aren't quite right, the sound is wrong, or some other minor issue. You can tweak most simple parameters like this without having to quit skyrim.
Simply modify your category source file, and then build it with SLAnimGenerate.pyw. You can do this while Skyrim is still running.
Next, go into the SLAnimLoader MCM menu, and in the "General Options" section, click "Reapply JSON Settings". This will update the settings for all SLAnimLoader animations that were already registered with Skyrim.
Whenever the SexLab animation registry is rebuilt, SLAnimLoader will re-register it's enabled animations. To unregister all SLAnimLoader animations, click the "Disable All" button in the "General Options" page of the MCM, then rebuild the SexLab animation registry.