Anchoring into the ceiling joist above the sheet rock will provide stronger support as the wood is a much stronger medium than the gypsum. To locate where the ceiling joist are, one may use a stud finder. The simple ones use a magnet mounted to swivel and work by showing when they are attracted to one of the hidden under the finished surface fasteners used to hang or install the sheet rock. Others are electronic and work by sensing density changes. Another simple method that works quite well is to wrap the back of the knuckles on the sheet rock to sense sound changes as the hand advances. It however requires having previous awareness of the joist directions. Once a sound change is detected indicating a near location of the joist, then a small finish nail can be used to identify exactly where the joist is. Once located, a screw fastener, be it a hook, eye or screw to hold a mount can be used.