Lock picking pin and tumbler locks can be a fairly easy process. Since a pin and tumbler lock opens with the key lifting the correct pins, you can take a thin, long piece of metal with a slight hook at the end of it and work with figuring out which pins need to be lifted for the lock to open. The other thing you need is a tension wrench, the simplest one is a flat head screwdriver. You apply pressure with the screwdriver and turn where the key would go just enough to get inside to start pushing the pins up.
Once you start messing with the pins, there is a particular clicking sound to listen for to unlock the lock.