java spring rest service

I have a working java app that do a simple process with 4 steps
that means I have a function I call that does all inside
I want to break that function into simple service with 4 functions

so right now I have on function I call it from the main function
it does step 1, step 2, step 3, step 4
each step starts and ends with a string value

I want you to build a spring service with 4 functions:
startAndDoStep1
DoStep2
DoStep3
Dostep4

the code is working