Crane offloading "Green Mountain Granite" flag stone.

 "Old Chester" (above) is an "obedient" stone to trim and shape. 

A fast  draining and well compacted base will prevent heaving  and uneven settling of flag stones.

1-1/2"  crushed stone compacted with stone dust.

Goshen flag stones with "glacial till".  The informal assembly of cap stones could be applied to a patio design.