The first, add online repositories, would be for downloading and installing the many updates while you are installing the system. Personally, I prefer to avoid that altogether, since I have on occasion run into Installation hangups doing this. Plus, it can take a very long time to do the install this way. If it does lock up, you have lost several hours and have to go through the process over again while holding your breath it will not lock up again. Trust me, that is a long time to hold your breath.
Much better to do the install through to completion, then run your updates once up and running.
The second, include add-on products from separate media, could be other programs or special drivers that you might need to install at the same time, say from some 3rd party disks, something that is quite rare now.
Leave them both unselected, do those things after you are up and running.