How do i represent myself for a first offense possession of marijuanna class b in court ?

The answer to your question is simple on the surface: insist that you want to represent yourself. Most courts will reluctantly let you do it, but it is really dangerous for you. You will lose your drivers license, have a permanent record for a crime and have to put it on many applications in the future (like apartment rental agreements, bank applications and more). When stopped by police they will see it and it may cause problems. For non-citizens it is a particular problem for immigration. Many counties have simple diversion programs that are not expensive and keep the crime from becoming recorded as a conviction. At least it would be wise to listen to an attorney to see what your options are.