You browse the Records Browser first by Record Type, i.e. "Sales Order", "Invoice", "Employee". There is no searching capability within the Records Browser, so all navigation is done manually. Record Types are organized alphabetically, so you first click on the first letter of the record type you are interested in, then select the Record Type itself at the left.
For example, if you wanted to see the schema for the Subisidary record type, you would first click on S at the top, then Subsidiary at the left.