First charge the battery(s) for the AC and the remote. Most P2's likely have been sitting for awhile meaning the batteries may need attention. Inspect the aircraft for cracks. Check the props, replace if necessary (P3 props will work fine). Then download the appropriate software from DJI. If you are using a PC hopefully you have one still running Windows 7. Getting the P2 software (mainly the USB driver) to work with Windows 10 is very difficult. Calibrate your remote and I recommend using NAZA mode to fly.
What may appear to be a good battery, could go south after 5 minutes in the air. I would suggest you look for an experienced pilot in your area, you might be able to find someone on this forum, to come out with you and show you the ropes. If you do wind up going out yourself, go to the biggest field you can find and stay away from trees. We've all gotten stuck in a tree, it's no fun.