I’m not familiar with this kit. I see a lot of interesting plywood pieces that I don’t know what they are for. And it looks like maybe 3 motor tubes and 3 sets of centering rings? Can you swap them out for different motor diameters?
Regarding Open Rocket, it is not my usual practice to use it during a build when I am building a kit. If I’m building a scratch built rocket, I use it to predict the size, weight, and stability of the design, but I don’t feel the need to do that for a kit. For kits, I figure that has all been worked out by the kit designer. I usually download a nice, thorough sim file for the kit. I don’t bother weighing each part and overriding mass for each one. I wait until I’ve built the rocket, and I weigh the whole thing and balance it, and then I put in a global mass and CG override for the entire rocket. You need that for accurate flight simulations. Basically Open Rocket has two broad categories of uses — planning a design/build and performing flight simulations. You don’t really need it to plan a kit build, unless you want to. But you should always use it for flight simulations, regardless of whether it is a kit, or scratch built, or a rocket you received already built.
I can’t really tell what kind of recovery gear it comes with. I often upgrade recovery gear for my rockets. If it comes with a flat chute, I buy a replacement with a nice design and spill hole. I like Spherachutes. And I get a kevlar or nomex chute protector and maybe a shock cord protector. Sometimes I upgrade the entire recovery harness too.
If you are doing dual deployment or any kind of electronic deployment, you can start sourcing your ematches and ffffg black powder, which isn’t always easy to find.
Good luck with your build and your cert flight!
