Ever had a job where you’re given no guidance and training and just expected to know what to do?

Could use some advice on this. I don’t know what to do here. There’s things that need to be done but zero expectations/ a lack of communication. Boss is always busy. I feel like my own boss. I’m making meetings with boss etc. to try to figure it all out, but damn if it isn’t making my anxiety flair up. I guess I’ll just make a lot of mistakes and hope for the best?