Download scenes, characters, etc from
https://f95zone.to/sam/latest_alpha/#/cat=assets/page=1/prefixes=35
Most uploads on there also feature dependencies for textures and models ; other majority can be downloaded directly through VAM's built in asset manager.
Organise the files, either through hiding dependency scenes in VAM or naming the actual scenes you like to have the prefix SCENE_ (for example)
Remember to delete scenes you don't like to avoid clutter and reduce overall size.
There are a variety of plugins you can use, I haven't used VAM in forever but there was one that would optimise shaders, physics and textures to increase your performance, shouldn't take long to find either on here or VAM's forum itself
These aren't the most "optimal" tips since i only used VAM for a few months, but these are mistakes that i personally identified and want to share with you to NOT have an awful experience like I did.