The only difficulty which might arise, is when you want to design the back cover in tandem with the front. Since it's the last page in the publication, you can't judge it next to it's printed sibling (the from page). But simply switch off the option Allow Document Pages to Shuffle in the Page panel's side menu, and drag that last page all the way up, right in from of the first page. Move close enough to the spine, so the little line which appears (as in the first image) changes into a thicker bracket (like in the second image). Let go, and presto !
(Yes, I drew than hand by hand, nice huh...)
In case your page numbering gets all mixed up, select the 2nd page (formerly the first) and choose the Section Numbering command from that same side menu, and state it to restrat from 1. It will tell you there's already a number one (yeah, the back cover), but there's no harm in that. You'll see another triangle appearing above the second page.