Use ⌘0 (macOS), Alt+0 (Windows/Linux) to display the Commit tool window. From here you can either press Commit to commit your changes, or Commit and Push to do it in one action. Alternatively, you can use ⌘K (macOS), Ctrl+K (Windows/Linux) to commit your changes, or ⌥⌘K (macOS), Ctrl+Shift+K (Windows/Linux) to commit and push your changes.
If you commit and push your changes you will be able to select your remote repository in the next step.