The Lisa doesn't have an alt-tab function for Window management, so I haven't added one. Also, it would be difficult to use those keys in particular because it would conflict with your system's alt+tab keyboard shortcut.
When you select text in a textbox, the keyboard should input text. Also, individual menu items have their own keyboard shortcuts. If you're on a PC, it defaults to using the Control key as the "Apple" key. If your on a Mac, it defaults to using the Command key. This option can be changed in the preferences app in the "Set Conveniences" pane.