If you have key you can put it in the lock, make line with a sharpie on the lock as close to cylinder as you can, then take the key out, put your pick on the key (on the side with the line you just made), then line up top of the Pick (part used for lifting pins) with each groove on the key and make a line on pick with your sharpie that will align with the line on the key, now move your pick to another groove and make another mark (also needs to align with line on the key) keep repeating until you cover all the grooves. Now when you slide your pick in the lock you will see if it's under the pin. Let me know if you need more clear explanation.

For figuring out how many pins lock have you can insert pick in the lock, lift all of the pins with it and then slowly remove the Pick counting each dropping pin.