If you are taking a formal course, ask your professor for the (many instructors will provide these). If you are self-studying, join the Coding Theory Stack Exchange and post your specific roadblock.
Why working through the solutions is the real secret to mastering linear codes, cyclic codes, and decoding algorithms. solution manual for coding theory san ling
The "solution manual" you need isn't a PDF. It is a workflow: If you are taking a formal course, ask