Is the trans brake useless or am I being stupid again?

Maybe there's a tutorial somewhere but I have googled it and the only things that come up are mods.

Simple questions: how does the trans brake work? Can you use the trans brake with the 2 step?

I'm using the Mooonhawk drag version. Engaging the trans brake, the 2 step works as normal in neutral, but when you engage drive the revs drop as the torque converter loads up. It seems from my experimentation that the trans brake is entirely useless compared to just using the 2 step in neutral and engaging drive to launch. Am I just using it wrong? I can only see one control in the menu, and that's just to toggle on or off, I'm completely stumped here.

 

It's pretty much a launch control but for drag cars

 

Transbrake and 2 step can be keyed to the same button (I use an Xbox controller) I use the top button above the right trigger to activate both. To use the 2 step, you have to use the buttons to dictate launch RPM, (go to the place where you set your window, choose vehicle, you'll find the keys to both activate and set the RPM. Like i said i use an Xbox controller, both keyed to the same button. How to set transbrake,(I'll use drag racing)
#1.Roll up to the line, stop where you wish to start
#2.Set the transbrake (whatever button/key you have setup), simple enough.
How to set 2 step, similar to the transbrake, but an extra step required
#1. As with transbrake, roll up to your starting point, stop
#2 As your brakes are still applied set the 2 step. That will put you in 2 step mode
Also of note, if you have the two step setup you can toggle the launch RPM, up or down (you'll have to figure out how it's setup default, i do mine on a controller)
it took me a long time to figure it out (only recently figured it out) Once you do, it becomes second nature

One last thing, 2 step is like real life, the limits are the same, torque converters can keep it from launching properly, if you need more, step up the converter to mid or high stall