Not confident with skills as New Grad which 3unit in hosp is best to start working?

I am a new grad and i am Not confident with my skills and having thoughts like "what if i make a mistake on the floor?" Or "what if i don't know what to do?". If able to start in a hospital, which 3 unit is the best to start in that gives best experience as new grad, slow to moderate phase, and not too risky?
I'm not sure I understand your question -- which 3 units are good choices for a new grad? I'm also not sure what you mean by "slow to moderate phase" and "not too risky". Could you please clarify?
The 'best' unit would be one that understands and supports the development process of new grads who are transitioning from student to practicing nurse. Seriously, there are just too many personal variables involved to make any sort of recommendation. Wishing you all the best as you begin your career.