Titan sliding mitre saw

Hi people I just bought the sliding titan mitre saw and went to change the blade tonight to a 60tooth blade for cutting kitchen cornice but I couldn't figure out how to change the blade. There is a large headed screw on side beside blade guard that looks like it has been chewed already (not by me) and there is a square headed bolt holding the side plate onto the saw underneath guard. I only.received an Allen key in the box so I don't know how to change the blade without a square headed Allen key. Stuck so please let me know if anyone has changed the blade on this saw.
Cheers