All the Menzerna polishes have a scale on the back of the bottle with an arrow head on the cut scale to show how much cut the compound offers.
Your pads will be in a similar scale from cutting to polishing and then finishing. Usually different colours for the different levels but the density of the foam and the firmness is what makes the difference in its abilities.
Generally you should start with the least abbrasive compound and a finishing pad to machine polish a car. Work the compound into the paint and then check the level of correction obtained. If it isnt enough, step up to the next level of cut on the compound and keep the same pad. Try this and then check. Essentially you are looking for a pad and polish combo that works for you. you dont have to use a high cut pad and polish to get results. in some cases you can actually make more of a mess going in too heavy at the start.
A lot of heavy cut polishes and pads will not finish down to a level that you can then seal, glaze or wax. They will leave polishing damage such as marring or holograming that then needs to be polished out using lower cut compounds and finishing pads.
SRP has its place but it you are going to use the Menzerna polishes to machine your car it may as well stay on the shelf. SRP is filler heavy and does actually contain abbreasives (albeit very fine ones). You will be aiming to polish out the swirls and scratches that SRP covers up so there should be no need to use it.
For a true finish you should also consider an IPA wipe down after polishing with a compound. Most compounds are oil heavy or contain some light fillers so can hide the true finish.
As mentioned glazes will add gloss. Something like DoDo Juice Lime Prime Light is an easy step to add into a full detail. This will also ready the finish for wax or sealant.
I've mentioned the many different types of sealant in another thread reply but after polishing you can use a dedicated sealant to lock in the work / finish you have achieved and then wax on top of that.
Someone mentioned DetailingWorld... best piece of advice in this thread. You need to read all of the guides around machine polishing and look at some of the techniques the guys use on there. You will also pick up a hell of a lot of tips and info.
Other than that, take your time. Read as many guides as you can and remember to go in light handed with the machine. A DA is much kinder to the paint than a rotary but it can still make a mess if you are not careful.
HTH, Nige