To move the cursor a page up and down, you have to use SHIFT-PAGE-UP and SHIFT-PAGE-DOWN by default. If you want to scroll a page up and down and move the cursor, you can change the key bindings.
[ { "context": "Editor", "bindings": { "pageup": "editor::MovePageUp", "pagedown": "editor::MovePageDown" } } ]
Open a large document and use Page Up and Page Down to move the cursor up and down.
The Zed Editor documentation shows a link to a default.json file, where you can see all default key bindings.