Howdy!
There's nothing guys can do that you can't.

It might be a question of degree: a guy might be able to do more pullups, but I'd bet there are plenty of guys out there that can't do as many pullups as you (or at least eventually). Don't sell yourself short.
I would start with the APK WOD; the APK warmup is often workout enough for people and that's okay. You will build slowly to doing the workout. I would guess that a lot of those conditioning moves are familiar to you via softball training so you probably are okay in terms of not hurting yourself with those. If anything is new, there are great step-by-step photos and explanations for every exercise in the WOD on this site. You can just link to them.
With regard to actual "parkour moves," don't try to bite off too much at once. Start with just rolls and short drops (a foot or less). Look at the tutorials for rolls and drops here in the
"How Do I Get Started?" article. These will take a long time to get down well, but it's worth the time investment. These are probably the two most important "moves" in the discipline.
As to finding a group, you will have to do some legwork. It may be that you get a group together, and you are all beginners! Given how new parkour is, it's very likely, in which case they may very much look to you to be the "leader" (which is different from being the expert, so don't worry if you don't feel you know enough about parkour yet--be clear that you are all beginners, and put the focus on learning as a group. It doesn't take any parkour expertise to organize a group of people to set up regular training sessions and communicate and make plans.)
What my group and I did was we picked a regular training schedule: same 2 days a week, same time; and then we keep our eyes open during the week for training spots. Every training day we meet at a different spot that we agree on, and then we do the APK warmup, and then mess around at the spot. Most of our stuff is very basic, since we are all beginners. Sometimes we play "Hot Lava" or "QM Tag." Other times we'll set a theme to the training, e.g. precisions or vaults, where we drill those moves in as many ways as we can. We almost always still practice rolls and low drops.
After a while it just sort of happens.
I hope that was helpful! Good luck to you!