I'll assume you have all three source tables loaded into your Power BI Desktop.
Click the "Edit Queries" button in the ribbon...
...to open the Power BI Query Editor (PowerQuery).
Then click the "Home" tab, then the drop-down arrow next to "Append Queries", and click "Append Queries as New":

Select the "Three or more tables" radio button, and make sure all all three tables are listed in the "Tables to Append" list, so the dialog box looks like this:
...and click OK.
It'll create a new appended table, named Append1, that looks like this:

Then click the "Home" tab, and "Close & Apply" to load the new "Append1" table into Power BI.
(If you don't want the "Age" column included, you can remove it before you "Close & Apply." To do that, just right-click the "Age" column and select "Remove.")