I suspect many of you use the free version of EPC available at the following. There's a paid version as well; not sure what that gives you vs. the free offering.

https://epc.startekinfo.com

I tried acquiring a free subscription last night using an American Express card. Kept getting "error please try again later" type messages. Opened an issue with MB.

This A.M. I was told there were issues with acquiring access to the free version using either Amex/Discover. They suggested VISA. Tried that and have gained access.

There's a beginner and advanced tutorial. It may not be rocket science, but it appears to be a bit more effort than your typical online parts sites.

I will get my feet wet soon hopefully as I plan on using this MB parts site to help trouble shoot issues with my MB.

Hopefully it will help others here as well.