press the button to M and use the 1/2/3/D to shift...its not like in automode, where if you put it in 3, itll go from 1st to second to third...whatever gear you have it in while in "m" mode, itll be in, so from a start, put it in 1, then shift to 2..etc
you dont want to press the brake while doing it, all you will do is lose RPMs. Like speedster said, you remain in that gear until you change it, so if you stop in third, you will have to change it back to first or else you take off slow(er than usual) and you may stall. You wont gain much from it, should have gotten a 5speed. If I drive over there while your there Ill let you try on mine. I told dad to try and teach you on the boxster when it leaves the shop, but I doubt he will. Took me years to be able to back it out of the garage just to wash it.