Camber is going to happen when you lower the car. You need camber plates to adjust to 0 camber, if that is what your shop thinks you want. Ask them what degrees camber you're at for each corner.
Installing them isn't very hard. Basically thy replace the top parts of the struts. i don't know that there are very many guides out these but try BMW DIY.com
. No offense, but after installing a couple dozen e36 & e46 suspensions and being a very busy person I won't be able to walk you through it. All I will tell you is to be careful and logical (very logical --> extratime here) regarding th eproper direction and assignment of th eleft and right camber plates.