I too am new to polishing modern paints and only a short while ago was asking similar questions. If you want polishes now have a look at the Autoglym products - you will pay more in Halfrauds but you can pick them off the shelf.
If you start reading some of the "detailing" forums either here or at A world for detailers...
you will learn more in a few hours than you thought ever existed when it comes to polishing paint and finding the best product for your paint and your colour - it seems some polishes are better onr dark colours and some are better on light colours.
For the final finish (if you aren't going to use a wax) then Autoglym super resin polish is great stuff.
And also have a read about "claybars." I used the Autoglym one on my wifes 159 and that smooth finish has to be felt to be believed. Be careful though as before you know it you have spent nearly £100 on paint finishing products!!!!!!