Welcome to this very information-filled forum! The first thing is to get out that owners' manual and read it from front to back...very important! Second...white smoke at start-up can and is usually caused by the very design of the flat6. It is oil that is burning off...mostly..however, if the smoke "screen" lasts for more than a few secs (30+ secs. is a little long) or is a funky colour, ie blueish..it needs to be gone over by a mechanic. The light that is illuminating with a picture of the spolier, is designed to turn off after you reach a "moving speed". (discussed in the manual).
And again...welcome to 986 forums and the wonderful (and sometimes frustrating) world of Boxsters!!!!!
oh and p.s.....the search function is your friend as well!!