How to remove head? I don't want to break ribs.

I am removing head from my parts bike. There should be some place to use a screwdriver as a lever.

There is no place to insert a screwdriver or lever.
You need to tap fore and aft with a slight upward blow on the round plain casting that clears the cam sprockets.
Use a soft mallet (rubber) alternating between front and back which will rock the head and break the head gasket seal.
Don't forget the two 6 mm bolts (10mm heads) near the outer spark plugs as well as the 12 head nuts.

Make sure ALL the bolts are out first. Look in the camshaft tunnel to see if there are 2 in there. Ed

Thanks.