You can find further information on this topic by checking out the Moonraker documentation.
To use the built in Update Manager it must first be enabled by editing the moonraker.conf file:
cd ~/klipper_config sudo nano moonraker.conf
Add the following section to your printers moonraker.conf:
[update_manager] [update_manager client mainsail] type: web repo: meteyou/mainsail path: ~/mainsail
sudo systemctl restart moonraker
With the manager enabled reload the web ui and select the ‘machine’ tab from the sidebar. You should now see the Update Manager panel.
Holding shift whilst clicking the browser’s refresh button (or pressing ctrl+f5) will force it to reload the page fully (without the cache).
Typically the update order is top to bottom.
To update a component, click the button.
A new window will launch and the component will be updated. When the update is finished, the window can be closed.