Does anyone know where the switch to turn on wifi signals on a dell laptop is?/

What is the specific model of your Dell laptop? One option is to check the Dell website and look under support for your particular model. You can probably download a user's manual from the site or simple view it as it more than likely a .pdf file. I don't know about Dell computers but on some it is either on one side of the laptop or a key combination (Fn + F?) . If it is a key combination you would press the Fn key and the function key (for example F10) that has the WiFi signal logo on it (usually at the top of the key and the same text color as the Fn key).