When it comes to warming up before practicing parkour and free running you can't really go wrong. Warming up properly is important in preventing injuries when training and helps aid you in learning moves more efficiently.
You can see demonstration of a warm up in this video:
Here are some more tips for your daily warm up...
Think mobility and movement, if any part of your body is stiff then you aren't warmed up completely yet. When beginning your warm up use basic exercises to get the blood plumping to different parts of your body. It also starts activating your muscles so they are quicker to respond when you actually start training. It's called the warm up because your body should be very warm if not hot at the end of it. If you are sweating that's a good sign you are warmed up.
Exercises that are great for warm ups.
Quadrapedal Movement (as seen in video)
And anything else you can think of. Sometimes I invent my own exercises to warm up certain joints or muscles.
You don't want to reach the point of exhaustion during your warm because then you might be too tired to safely learn parkour moves, but don't be shy with your warm up, you should still push yourself. Most of the injuries I have received through out my years of training I can blame for not properly warming up before doing parkour that day, and that is probably the most important reason to warm up.
Important parts of the body to warm up/ stretch:
Sometimes the warm up can feel tedious so be sure to find ways to make it fun. I personally found doing the quadrepal movements quite fun and they work really well for working the legs, arms and core. Some versions of quadrapedal even mimics certain vaults improving you coordination to do moves that involve your hands and feet.
Good luck in your work outs and remember to drink lots of water!