Do you feel difficult to come up with a plan to built it? or to implement the plan?
I used to teach robotics in middle and high school. Some of my students were good at coming up with ideas, and some were good at putting things together. Not many were good at both but that’s all right.
If you don’t know where to start, may I introduce the FIRST program (https://www.firstinspires.org/)?
If you would consider mentoring kids, there’s a good chance that there are FLL and FTC robotics teams near you. You can look up registered teams here Team and Event Search | FIRST
Team mentors are not coaches. They can provide support in many ways. If mentoring feels too much, maybe you would consider volunteering at competition events? If you follow a team or two for a season, you can see how they go through the design-build-test-modify cycle. Many of these team members, especially the FTC and FRC team members, want to study engineering in college. You can give them much insight.