Ah I'm tempted to write a complete guide:
In restaurants you open the door and wait for someone to ask you how many seats, you get taken to a table, you sit down and look at the menu, choose what you want to order (usually drinks first. If you don't want to get any, tap water is free)
A waiter/waitress would take your order, if you have any allergies, tell them. Then wait until your food arrives (could take from 15 min to half an hour. Any longer than that, ask if they've got your order down)
Then eat the food. After you finish, just wave to a waiter and say 'bill please' then pay.
That's it. If you have any other problems, just wave and ask a staff member and they'll help. If you're really worried about this, find someone to go to a restaurant with you.