Doing belt for 1st time is just one of those things, you certainly learn after you keep putting the belt on and off.
I kept getting one pulley just one bloomin tooth out, very frustrating.
The trick is to gently hold the belt on one pulley with a clamp then work away from that pulley.
You aslo need a good wide vice to squeeze the tensioner back up.
Toughest bit was getting the bloomin crank pulley off to get access to the oil seal.
Just seemed silly not to do water pump,thermostat and oil seal whilst it was appart.
The belt i took off was nearly 7 years old but looked perfect, mind you had only done about 30k if that.