Have the payee endorse the back of the check to you. He must write "Pay to the order of" and write your name.
Have the payee sign beside or beneath the endorsement. Sign the business check under the payee's endorsement and signature.
Take the business check to a teller at your bank. You may have to present the check in the company of the payee. The bank may request the payee's proof of identity or an endorsement guarantee before it is willing to accept the business check and deposit it into your account.