Download the 10.x release from kicad.org/download.
.dmg, drag KiCad to Applications. Open it once from Applications so macOS trusts it.sudo pacman -S kicad kicad-library kicad-library-3d on Arch; Ubuntu users add the ppa:kicad/kicad-10-releases PPA, then sudo apt install kicad).Launch KiCad. The first-run wizard appears. Click Next on every page and keep the defaults, in particular "Copy default global symbol library table (recommended)" and the same for footprints. That gives you the stock KiCad libraries. The team library is added per project, below.

The first-run wizard. Next, Next, Finish.

Keep "Copy default global symbol library table". Never point these global tables at the team library.
xcode-select --install in Terminal, or install from git-scm.com.sudo pacman -S git or sudo apt install git.Optional but handy: the GitHub CLI, cli.github.com, then gh auth login.
Tell Git who you are:
git config --global user.name "Your Name"
git config --global user.email "[email protected]"
Every Reality Labs board repository carries the library as a submodule at kicad-library/, next to the .kicad_pro file. Clone with the submodule:
git clone --recurse-submodules <https://github.com/uwrealitylabs/><project>
Already cloned without it? Run git submodule update --init inside the project.