There are 14(?) bolts with allen key heads - 10mm, available from any auto parts retailer. The bolts are accessible without removing the camshafts.
The 3 down the middle have nothing to do with holding the head onto the block.
There are also 3 small 10mm head bolts, 2 at the rear, one at the front (driver's side).
Undo from the middle outwards, alternating front and rear.
ie: 7/8, 5/6, 9/10 ...