generally, you create a big loop (ok it's already present@arduino sketches). Inside the big loop you do this
- read all the inputs lets say to variables, and then calculate what you are going to do / to change at the outputs and what to display
- write the display
- set the outputs
(then the loop starts again)
That's it already. If some output or display are not time critical, you can run counters and update them only every n loops.