The entrance is on the right. In general, Yosemite is better for Spring and Fall climbing - you may be able to climb in April and as late as Thanksgiving. Rescue is not a certainty. If you get into difficulties, be prepared to get yourself out of them. Know what to do in any emergency, including injuries, evacuations, unplanned bivouacs, or rapid changes in weather.
Safety depends on having the right gear and the right attitude.
Courtesy is an element of safety. Falling rock or gear is a serious hazard. Be careful when climbing above others. Do not create a dangerous situation by passing another party without their consent. If you are injured or stranded while on a climb and cannot self- rescue, yell for help to obtain assistance.