The experienced striker was out of contract at Hereford, also relegated to League 2, and he turned down a player / coach role at Edgar St.
Guinan scored 15 goals last season in a relegated side.
"I am sure Steve will score goals for us. He has a lot of experience and that is vital," said Gray.
"Steve is a student of the game who has his coaching qualifications and he is a very intelligent player who can pass on his knowledge to the younger lads."A few times last season we fell flat but he can be a leader and he can organise and he has won promotion from this level on more than one occasion so he knows what is required.
"He scored 15 goals last season in League One in a relegated side and he was their player of the year, so he comes with a decent record.
"We need plenty of talkers out on the field and Steve will be one of those."
Guinan starts officially on July 1st.