There are several ways to enter your own data. Here's the easiest way to begin.
For a new spreadsheet using the Mapping Sheets add-on, you will be asked to create a sheet named Data to hold your information. You'll have the option of using some sample data to play around with, or you can get started with your own headers and data.
In either case you will be getting a new sheet named Data. Here's how it looks using the sample data:
Headers can have any name and order, this is just an example. You just need to choose which column (header) you will use for Title, Filter and Location.
After that, you can enter your information by copying and pasting it or typing it directly on the sheet named Data. You can proceed by clicking Build to process the information, then View to open your map.