First, get near a wall in your room or somewhere else with carpet (in case you fall).
Stand with your back facing the wall.
Put your hands against the wall above your head to support yourself, and slowly bend backwards.
"Walk" your hands down the wall until they reach the ground in a backbend position.
Repeat until you are comfortable using the wall. You'll probably want to take a break in between, or else your wrists will start hurting.
Try doing the backbend without the wall. Remember not to do it on hard floor!
With patience, you should be able to do a backbend while you are standing up!
The creator of this guide has not included tools