You turn it on by pressing the green button on the battery once for low power and twice for high, although to be honest, there is not a lot of difference between them. After that, you just pedal. There are no gears, no chain to muck up your trousers (a motorbike-style carbon fibre belt is used instead) and not that much difference in feeling compared to riding a normal bike.
If you're taking your bike inside, consider one that folds up. The Cyclotricity Wallet has a motor in the front wheel, which takes you up to speed either by assisting your pedalling, or you can sit back and use the throttle by itself. Its folding design makes it slightly easier to get in and out of a building, but its hefty weight means you still won't find it easy to carry onto public transport.
The U.S. Consumer Product Safety Act states that electric bicycles and tricycles meeting the definition of low-speed electric bicycles will be considered consumer products. The Consumer Product Safety Commission (CPSC) has regulatory authority to assure, through guidelines and standards, that the public will be protected from unreasonable risks of injury or death associated with the use of electric bicycles.
On the other hand, the battery doesn’t lock into the bike, which means you can’t just leave it on your bike when you park at the bike rack. Anyone could walk by and simply remove your battery. That seems like an oversight to me, though perhaps the designers assumed that such a small battery would just be easy to take with you. And it is. My wife could probably lose this battery in her purse.