Hello Yannick B.
Once you have enabled iTunes Match and then add music from a CD, it will automatically add those to iTunes Match for you or you can go to a drop down menu Store > Update iTunes Match to add the tracks. If you have iTunes Match enabled on your iPhone, you will see the changes rather quickly once uploaded.
If you want to delete music from iTunes Match, just delete the tracks and a prompt will ask if you want to delete from iCloud. That should answer those questions for you.