One of the main navigational aids is to apply a structure file to the data file, which provides one or more layouts in which to present each record in a much more user friendly way; see Creating Structure Files and Layouts for more information.
There are also navigational arrows (or you can use the cursor keys) to move from one record to the next. You can also jump directly to a record by entering the record number in the Record Number box.
For larger data files, an easier solution is to search the file for specific information. The search allows you to use multiple criteria in order to filter the records that are displayed. After the search has been applied, you can switch between the entire file and the search results using the View option.