Combing code for hall effect RPM and Nextion tacho

I think the saving it as RealRPM is my issue that Im having I dont know how or where to do that.

I may be missing the forest through the trees on this and could use a hint on it.

I keep thinking I need to blend them and maybe thats not necessarily the case where I can just paste them together, but the HallTach code serial.write as its own entity has me mixed up. How do I make that RealRPM instead?