You can select a branch at the upper left. When you selected the right branch you need to press the sync button (upper right) which does now the same as git checkout BRANCHNAME
.
In the older version you are able to view 2 different branches at once and compare the pushes. Furthermore you could view a timeline of your project (see beneath)
Creating a new branch
You can create a new branch by clicking on the branch symbol (old client) or under File --> New Branch
.
Note that you can select of which branch the new branch uses as base by clicking on the branch name.