I am unclear on the instructions regarding the second rise. Your instruction say to heat the oven in the last half hour of the second rise - how m...

The recipe says "for an hour or two." It will depend on how warm your kitchen is in the place where you're letting it rise. I'd look at the dough, very gently unwrapping it, after about 30 minutes. Does it look like it's rising pretty well? Does it look like it's increased in size by about 1/2? If so, turn on your oven. If not, check in another fifteen minutes. If the dough hasn't fully risen by the time the oven is hot, don't worry about it. Just leave the oven door shut until you're ready to bake, so it stays nice and hot. ;o)