Groups in BodySlide are multiple project entries bundled together under one name. They can be used to filter the outfit list and/or choose which ones to use for a batch build.
A guide to editing the Skyrim configuration settings inside the INI files for the tinkering user.
STEP recommends installing Skyrim to an SSD, if available, and preferably on a separate drive/partition than the Operating System is installed on (i.e. instead of installing to the C: drive, install it to D:, E:, etc).