As a child I had a very basic bike - no gears - to play about on. Now 50, I can still go a bike - as in getting it go forwards and stop without me falling off.
But, the bike I've got has gears and I have no idea, at all, how this works. I'm a car driver - if that helps with explanations.
The bike has 3 gears on the left and 7 on the right!
Help! Please!