Next to the volume control is the network control. Wifi is practically everywhere these days, so switching to a different network is a common task.

Clicking on the network icon brings up different network options. If a wireless network has a closed lock beside it, then you need a password to join. If you don't know the network password, ask the owner of the network (for instance, a waiter at your cafe, or your IT person at work, a roommate at home, and so on).

If you need more networking options than the drop down menu gives you, select Wifi settings. A new window appears, where you can perform advanced tasks like re-configuring interaces, creating new interfaces, getting your IP address, set DNS servers, and so on. You normally don't have to worry about these details, as most networks configure them automatically for you.