Well, it depends on what kind of bike you have, how much pressure it will take to get going. If it's a single speed or 3 speed and you're starting uphill, it might take most of your weight (don't start uphill if you can avoid it). If it's got shifters and deraileurs, then you should shift into a lower gear before you take off. That means at least your chain should be on the front ring closest to the center of the bike, at least until you get the hang of it.

Pedals shouldn't really break, unless they're plastic. They're designed to take all your weight plus any pressure you can put on them to make them turn. Use the ball of your foot, not the arch. There is a more technical description of what part of the foot, but it's best not to obsess over it. If you can use the arch of your foot comfortably, it's likely that your seat is too low.

What kind of bike do you have?

Karen