As you might or might not know, the excel streamer only shows 10 channels from default.
I have made a menu with more then 20 different settings, which i want to register into the datastreamer. But i cannot find how i can expand the 10 channels into more channels
Can barely find anything online, can you help me? 
Assuming the spread sheet is not locked you can copy and modify the existing formulas.
I suspect that you have encountered a hard limit in datastreamer; there is also a limit on rows (500 max; source Increasing live data in Data Streamer | Microsoft Community Hub).
So what you want might not be possible. But you can ask on other fora (like the one linked; I think that you have a better chance there.
As this is not really a programming question I have moved your topic to a more suitable category on the forum.
Go to the "Settings" Tab. (Sorry, I don't know what it is called in your language, Is it "Instellingen"?).
Then you can set the number of Data Channels:
The pop-up message says you can have up to 1000 channels.