Unclear expectations in job

I think what I am most frustrated about in my job is the lack of clarity I have about what my role and the expectations my boss has of me. I have struggled with this from the beginning. I have asked him how he would recognize success for his employee, what his ideal is for my role (what the person would do, etc) and he said that if no one is shouting at me, if he continues to give me work, if we continue to get things done. He wants an employee who can build websites because he can’t do it anymore. That’s probably the most specific piece of feedback I’ve gotten. And so, I am thinking about how I might show up inside of a job where the expectations are unclear. How do I meet expectations and know I am successful if I don’t know what that means for this job? Do I come up with it for myself, regardless of the job that I’m in?

C: web designer job
T: I don’t know what my role or expectations are of me
F: doubtful
A: question myself
R: I have no idea if I’m doing a good job

C: web design job
T: I’m going to figure out how to be the best designer I can be in this job
F: empowered
A: work to figure it out
R: I am not at the effect of my boss or my job or anything outside of me