If you'd like to eliminate the inconvenience of manually opening Salad every time you boot up your PC, you can enable Auto Launch. To do so, first open your Settings page by hovering over your profile at the top right, and clicking "Desktop App" on the right, as outlined in red below:
Next, click the option to enable Auto Launch by switching the tab, pictured below, to "On."
This will allow Salad to open automatically once you log into Windows. If you'd like Salad to begin mining automatically when you go AFK, you'll need to enable Auto Start as well.