Peter,
You can add the movies to iTunes by (a) File > Add File to Library, (b) File > Add Folder to Library or (c) Drag and Drop to "Library" in the left side Sidebar (View > Show Sidebar).
When you connect your iPad to the computer with the sync/charging USB cable, it will appear as a device (after a slight delay as it's being recognized). You can choose what data you want to sync to the iPad (music, videos, contacts, calendar, etc.)
If the files show up as TV Shows and you want them to be categorized as Movies, you can change the Media Kind under Edit > Get Info > Options Tab.
Steve