It looks like you've been given a lot of leeway so you first have to decide what you are actually trying to control. Based on my reading of your spec most likely you're trying to maintain a tank level. If one pump can't do the job, you start the second. If that's still not enough capacity you add the third, etc. Similarly, when the number of pumps is more than the demand calls for, you shut them down in sequence.
First, answer some basic questions. Is the pump motor going to be controlled by a starter or a variable speed drive?
Depending on your choice, what are you going to need for PLC outputs?
What are you going to use to sense that a pump is running?
What other sensors are you going to need based on your choice of control strategy?
Once you have selected a control strategy, figure out how to get a single pump running and controlling the system. Once you have that working, duplicate the logic for a second pump. Then figure out how you will detect when the one pump isn't getting the job done and how you can use that information to start the second pump.
The overall task can look overwhelming, so break it into smaller pieces that aren't as complex.
good night friend, would you charge how much to translate a clp programming from onron (cx one) to simatic 7 (tia portal v15 from siemens?
there are 17 pages with two columns of ladder programming in cx-one.grato