First of all,
welcome to the Forum!

The MPPS is a pretty good all-rounder, it can read a lot of ECUs.
To answer your questions, although I have no experience in using a MPPS-Cable to read the ECU of a ME7.5. It's pretty obvious that you can use the output file and import it into WinOLS.

You need ECU Definitions for all ECUs in WinOLS. You can find some Mappacks on here.

A good advice from me is that you read a lot through this forum and start with something simple like Pops and Bangs, or just increasing your Speed Limiter or RPM Limiter.
You won't find a lot of people who are willing to tell you instantly what you have to do without giving back to the community first.

I hope i was able to help you along.
Have fun