For stock German paint you need an orange pad and a white pad.
I use Menzerna polishes.
FG400 with the Orange pad and SF4000 with the white pad.
You can use a single stage with the PF2300 on a green pad if you really like.
As you are a beginner I would recommed watching some Youtube videos and reading some guides as you can easily get it wrong and make it look much worse. Even better would be to buy a scrap panel and a sungun, around 40-50 for a Brinkmann Dual Xenon - And even better, a paint depth gauge. Around £70 on ebay for a cheap one..
Autoglym SRP and HD wax are completely different products, one is a paint cleanser/filler polish/pre-wax cleanser and the other is a wax also known as an LSP / Last Step Product which is what you'd put on the car after you've polished the paint to protect the surface from UV rays, industrial fallout and provide nice water beading characteristics and an element of self-cleaning capabilities.