You probably haven't been exposed to very many different brands and models of PLC. If you had, you would understand that there can be significant differences among different brands as to instruction set. One of the most significant outcomes of your technical education should be learning how to ask a technical question. So far, you're getting a failing grade.
Furthermore, most of us here are opposed to simply feeding answers to students. We'd like to believe that the student is interested in learning about PLCs, not simply in getting a passing grade.
So, tell us what model PLC you're using. Also tell us about the 7-segment disply. Is it BCD coded? What types of signal does it require to make it work? How do you think you could make your PLC furnish those signals to the display?