... and some got answers, of different depth and quality from different sources.
As I like to have things explained in a way I can understand, I want to share the answers I got while seeking for answers.The first usable guide I got was from Michael "Steele" Boewes. He did a fairly good job with his HELP Quide. Be shure to visit the rest of his Site, too!
Then I found a three part description at a Site I cannot remember. It is a 3 level guide, from basic OPT replacement to advanced slot editing. Be shure to save or print it!!!
Last but not least I decided to do a graphical summary and explanation, in order to make things more "visible". I hope you will enjoy it! Be shure to have your browser at fullscreen or it won't display correctly!
If you wanna print it, I suggest to choose landscape orientation and/or scaling, if your printer driver supports it.