How can I increase my MB upload size?

Dear WPMU,

Pls let me know how I can increase my media, upload MB. I already tried a lot but nothing worked out for me.
Pls give me detailed instructions to solve this issue.

Furthermore, I sent you an email last week about two languages on a wordpress. Pls send me an answer to that as well. Thank you very much for your great support.

beste regards
Ratschi