Where every square is stitched, it's fine to start on p.1 in the corner. You can start at the bottom, too, if the pattern is touching the bottom border. Most advice is to start in the center of the pattern. Look for the arrow on top & on one side. Draw lines across horizontally & down vertically until they meet. This is on the copies you've made, of course. Most designers allow a working copy which is discarded later.
You should allow 3" on each side for framing. To start in a corner, simply count down 3" & right or left 3". Being off a thread or so won't matter.