Generally, the Map In XL tab automatically appears in Microsoft®™ Excel®™ when you open it.
If this tab does not appear, go to the Excel®™ main menu, then to Excel®™ Options. Choose the "Add-in" menu and go to "Manage" > "Disabled items", then "Reach".
Tick in the box in front of Map In XL Addin, and click on "Activate".
The Map In XL tab will appear at the next start of Excel.