it is the same thing as a cell phone and how it works except it is only data and not voice/text enabled. i'd assume you'll see network settings and such pop up once the sim is inserted. i have an old phone i use as a media device with no sim card and other than the missing sim warning in the notification area, i see none of the normal mobile settings that are usually there.
as a cellular network user it'll still have normal issues of weak/slow signal and all the other joys of cellular data so keep that in mind. also keep close tabs on the amount of data used by what app. some use a ton while others sip it especially with various video services. even had a few games i tried out use over 100 mb a day of data for whatever it was doing. manage that data wisely as even an unlimited plan is pretty much never actually unlimited. the fine print always gets ya before you know it's there.
youtube and netflix uses very little data for me but something like NFL mobile app streaming a game can use 2 gb for a single game!! did not know that and blew through a month's data in a single weekend one time