Can't move on

I've really just begun but there is a stop sign at the end of most streets. The only one without a stop sign, shows a button but it is not playable. How do I go on??

Try clicking the button that's not playable. It should open a box that has a "play" and "back" button. Click the play button and it should take you to the shop to buy the necessary item for that level. If you don't have enough money you can replay the previous levels which allows you to earn the money you make each time you replay it.

I hope this helps.