Indesign: Master pages not applying correctly in the right order

I'm guessing this is a pretty simple problem I'm having. I'm new to indesign and can't figure out how the masters apply to the pages properly.

For example, I have a 3 page master and I drag down the first page - fine; I drag down the second page - fine; I drag down the third page and the first page displays instead of the third. It also happens when I try to put the first page of a 2-page spread on the right-hand page.

Is there a setting I need checked or unchecked for this? What am I doing wrong? Sorry if this is a really simple problem.