How do I hook an old ps2 online?

how do I hook the old ps2 up to get online

I researched this for you and it seems you need a router that connects your ps2 to the internet.
If you have the old ps2, you need a network adapter and you need an ethernet cable that connects the ps2 to the router.
Other than that, allegedly it's free and setup is supposed to be easy.
Once you get in a game, you are to go online and it walks through for you

Buy/achieve a network adapter, screw it into the back of your PS2 where the big open space is and bing bang boom, throw in the ethernet wire, that'll go from your computer (if it's hooked up to share internet) or online router (much easier if you have one) and you should be online just go to the online menu for whatever game you're trying to access.