This is not a bad start. And don't worry about the APK warmup being a challenge. It is for most people. You will work up to it with consistent practice over time. If you're comparing yourself to people like Demon and Steve, that's silly. They're insane beasts, kind of superhuman.

The rest of us mortals plug along more along the lines of regular folks who like to work out a lot.

Here's what I would suggest you work on:
Pushups
Squats and lunges (standing lunges and walking lunges)
V-sits, hollows and hollow rocks, and L-sits (situps aren't terribly useful; use these instead)
Wrist conditioning (there is a thread somewhere; Steve's rice bucket idea is a good one)
Box jumps
Pullup progression: negatives, body rows, hanging, chins
Running
Roll drills
Landing drills
Precision drills
As to how to do all these things, search for threads, and find a lot of the exercise descriptions on the APK main page under "Fitness." Honestly, if you use all the exercises on that page like a "buffet" and pick and choose some from them every day you will be conditioning well, although not in a very structured/systematic way.
Even better: do as much of the WOD as you can, every day. Even if it's just part of the warmup. Eventually you WILL get better, I promise. It doesn't happen overnight, but it does happen. 1 + 1 + 1 + 1... a million times still equals a million.
The most effective way to train is to do so in a structured way. The WOD creates this structure for you. It is up to you to scale/modify it to your fitness/ability level. Over time your skills will improve and you will be able to do more and more.
Alternatively, read Steve's article
here and structure your own system based on your needs. As you will see in the first paragraph, the first thing you need to set up a workout routine is GOALS. And no, "To be better at parkour" is not a goal. Goals should be measurable and should have deadlines, for instance: "To be able to do one pullup by my birthday," or "To be able to run a mile in less than 10 minutes by the end of the summer."
So once you set up some goals, we will be better able to help you with your training program.
Good luck!