This project is meant as a litmus-test for your proficiency at programming in C. It covers the very basics of being able to write useful programs. If you're struggling with this assignment, it may be a sign for you to take a step back, and get some more experience with C, as things will only get harder from here on out.
If you still feel you need more C practice after completing this project, we recommend doing the intial reverse project. But be mindful: The error messages that are needed to pass the tests are wrong! The provided text say "error: ..." but the tests expect "reverse: ..." so make sure to match the tests' expectations in your code.