For the most part, navigation through openDCIM is done from a top-down approach. The Data Center is the highest level container, and within that you have cabinets, which house devices and power strips. To see your cabinets, you select a data center, and to see your devices and power strips, you select a cabinet.
To the left of your browser window on most pages, you will see something similar to the image shown here. If you are logged in as a user with all privileges, all of the buttons will be visible.
Some pages can be accessed via multiple paths. Cabinets, for example, can be accessed either through the Edit Cabinets button shown here, or through the tree view below the buttons by clicking on a specific cabinet, or through the map method.
The tree view is expanded or collapsed by clicking on either the + or - next to the name of a data center.
The default search field is the Label (name) for a device, but if you click on the Advanced link below the entry box, you can also search specifically within the Name (or Label), SerialNo, or AssetTag, or CustomTag fields. As you type in your query, the page will automatically present you with the list of options that match your selection so far - basically like the search box in Google. Once you have entered as much text as you need to limit your search, click on the magnifying glass to the right of the text entry box to see the options presented to you, where you can click on them to go directly to their entries.