I agree with everyone else- follow Rose’s instructions, at least starting out.
You mentioned being interested in new frostings. Recommendations depends on what you’re looking for in a frosting. I think we all have our favorites here The classic and neo-classic are rich in a wonderful way. Although they can be piped, they are the softest. Neo-Classic may be the easiest. The Silk Meringues (my fave!) are custard-y and can be piped. The mousseline is light and pipes beautifully.
Whichever frosting you choose, I’d suggest watching your temperatures carefully. You really can’t go wrong with any of Rose’s frostings. I never thought I liked frosting until I discovered Rose’s. Now I have my teeny tiny freezer stuffed full of it.. and little else. Who needs veggies when you can have Caramel Silk Meringue??