Log in to your CodeSee account when prompted by the sidebar
Bring up the command palette using Ctrl/Cmd + Shift + P
Choose CodeSee: Open Review Map to review changes on your branch
Usage
When you're browsing a pull request locally, open the command palette with Ctrl/Cmd + Shift + P and choose CodeSee: Open Review Map. This will open a visual representation of your pull request.
use your mouse to drag the map around
use Ctrl + your mouse wheel to zoom in and out
click on a file to view its dependencies and tune out the rest
double-click on a file to open a diff view
right-click on a file to mark it as viewed -- this will be reflected in GitHub
GitHub Pull Request sidebar
When you're viewing a file inside the sidebar of the GitHub Pull Request & Issues extensions, you can create a Review Map of those changes without checking out the branch.