I also don't get the notes, "To get the rich
carmely flavor you need to boil your first gallon of wort very hard for
30 to 45 min." I am doing full boils so does that mean I need to just boil the whole batch hard or is he referring to a partial boil?
This refers to an AG process where you take the first runnings from the mash (steep) which are high in sugar, and boil about a gallon down to a quart or so, which produces mailard reactions (and maybe even caramelization?). This gives a more complex profile.
Maybe you could do this with extract by using all pale extract from a British brand (Marris Otter) put 1/3-1/2 or so into a gallon and boil that down to a few cups and then use the rest in your full boil. You can steep a little character malt (carastan) and/or do a long boil as well. I've never done this, but it seems like it would work.