Ok, you have GIT repository somewhere with some separated parts. You want to commit them separately, maybe from different computer. So, how you can do this?
Assume your repo have some example structure:
\my_fucking_repo
\part1
\part2
Somewhere on PC where you want to use part1
$ git config --global core.sparsecheckout true # or use local config, why not
$ mkdir my_fucking_repo
$ cd my_fucking_repo
$ git init
$ git remote add -f origin <my_fucking_repo url>
$ echo part1 >> .git/info/sparse-checkout # add all folders you want to work on this PC
$ git clone
IT'S DONE. Look what you have:
$ ls
part1 # only part1, motherfukcer!