Visit Otto.euc.it.umich.edu. On the landing page, you'll see a list of organizations and systems that you have rights over. On the left sidebar, you can search for systems or pair a new system.
In the searchbar, type a computer name, serial number, Mac address, or other identifier. You can use * as a wildcard, LIKE and other matching techniques. If the computer appears, click on it.
If the computer does not appear, it doesn't exist in Otto. Enter its serial number in the Pair A System box and click pair. When Pairing a machine, you're prompted to provide a Group and optionally, an Otto Name.
Alternatively, use the Pair Many Systems link to paste in space or comma-separated list of serial numbers to pair in bulk.
IMPORTANT NOTE: Pairing a system does not prestage it automatically. To prestage a system, see QuickStart: Prestage Computer. Note that you can prestage many systems at once using Bulk Actions on Systems.