If you don't have an existing local branch, it is truly as simple as:
git fetch
git checkout <remote-branch-name>
For instance if you fetch and there is a new remote tracking branch called origin/feature/Main_Page, just do this:
git checkout feature/Main_Page
This creates a local branch with the same name as the remote branch, tracking that remote branch. If you have multiple remotes with the same branch name, you can use the less ambiguous:
git checkout -t <remote>/<remote-branch-name>
If you already made the local branch and don't want to delete it, see How do you make an existing Git branch track a remote branch?.