How can I concentrate in studies over 4hour+?

take breaks and do time boxing

you can find playlists on youtube. Music really does help. Also having a calm and quite environment

I would be eager to learn this too :)

I'd suggest study in chunks, instead of 4 hours straight

Yes, you can - with good music, high speed internet, quiet space, 20-25 oC and a computer. Everything is possible.

Changing subject focus every hour