I got my staggered breaks messed up and left my year nines in the corridor for five minutes until one of them was brave enough to stick their head in and ask if they could come in, I could have easily been in the staff room!
I was a piss-poor trainee, I wasn't confident enough, had a 1 year old who didn't sleep, and sometimes forgot my own name, never mind their names, I only got through because I had 'nice' placements, my first term as an NQT in a rougher school nearly broke me. I had shit behaviour management skills, and the advice of the (large, male) SLT behaviour guru was 'just TELL them', yeah, that might work for you mate!
I managed to pull myself together after Xmas, and actually, now I can 'just TELL them'. I did three years there and I'm moving on tomorrow, I'm bricking it about being 'new' again!
They've replaced me with a teach first trainee, who's only ever done 3 10 minute starters, and is even more nervous and ineffectual than I was when I started, so I'll be keeping her in my thoughts this term.