Once you have your iPad, then you need WiFi.
You can find it in public places of course.
Here's a way to connect... from Apple. Tap or click for it.
But then you almost surely want WiFi at home.
You need internet service first of course, and for that you need a router with wireless.
(Alternatively, there are third-party adapters which connect direct to your modem, but then it is inconvenient to use your iPad in only one place.}
So how do you set up your router?
Here is a procedure for one popular router. Tap or click for it.
Other routers will work similarly.