How To Add Custom Poses/Animations Into XML Files.

So I'm creating a mod and I think I mostly understand things... But I do not understand how to add custom Animations/Poses to XML files. I have not made any pose's yet I've just browsed through the tuning files I extracted for the Get to work Group Photos. Also, How would I make Group Photos The studio and a singular camera mash Base game so everyone can use it to hang on their wall. I'm thinking of adding 12-14 People in a pose and having different poses to choose from when they take the picture. also, a way none has to man the camera. I can't find any articles on how to add custom Poses into XML files like SACRIFICIAL, BASEMENTALIST, And TurboDriver do... For their mods... I just thought I would do something I enjoy and a problem I could fix for my self so I don't have to make cc for family pictures.
Also, how do I change the Instances and interactions from an object? That is not mine but I got permission to use...

Not sure if I should upload any files because they are basically unedited so just comment if I need to upload them!

Thanks In Advance,
Bzeebee