Think of the 1062 as a OBi 200 built into a phone. It's a fully digital telephone; it doesn't need to plug into an OBi ATA; it has one built-in.
The OBi 1062 came with an Ethernet cable. Plug one end into the phone, and the other end into your router, just as you did with your 200 and 202.
Add it to your OBiTALK portal by clicking the "Add device" link. You can then configure the SP1 -- SP6 slots as you wish, same as you would with the 200 or 202. There are a boatload of other things you can configure, like the function of all of the buttons on the phone, which type of headset to use, etc. Unfortunately, there is no "dummies" guide. There's the administrator's guide, which you can download from Obihai, but that's it.