Edit ▸ Keyboard Shortcuts… (Ctrl+Alt+Shift+K) lists every shortcut. Menu commands show their shortcut next to their name. Help ▸ Keyboard Shortcuts opens the same list on the web: Keyboard Shortcuts.
Help ▸ Master Page Help (F1) opens these pages in your browser. Help ▸ Open Sample Document opens a sample to try things on. Help ▸ Other Apps shows the other Rainbow Factory apps.
Help ▸ Send Feedback… sends a message, with screenshots if you like, straight to the developers; Send Feedback (Form)… opens the same message as a form. Window ▸ Feedback (Ctrl+Alt+F) keeps the feedback palette at hand while you work.
Help ▸ Check for Updates… looks for a new version of Master Page; the edition installed from the Microsoft Store is updated by the Store.