Before stamping on my masterboard, I find it's helpful to first make a template of the folded booklet. (I'll share the folding steps with you below.)
First, I folded a scrap piece of copier paper and labelled the various pages, then I unfolded it so I could use it as a guide—it's a good reminder that the top half of the sheet will be right-side up, but the bottom portion is upside-down! (BC is "back cover" and FC is "front cover".) Note the cut in the centre, separating FC and Page 1 from 4 and 5.