Convert KML file into PLN using SimDebrief
Next step is to convert KML file to Microsoft Flight Simulator's PLN flight plan file. To do that, navigate to SimDebrief web site and click the Convert button as shown on the following screenshot.

In the next window, click the browse field and select the KML file from your C:\flights\ folder which we created on the previous step of this tutorial.

Browse to your KML file, and click Open button as shown on the following screenshot.

The KML file will be selected in the Browse field and you would need to click the Convert KML to PLN button as shown below.

The KML file will be uploaded into the web site, converted to PLN file and you will be able to see the replay of your flight together with flight information on the flight details page.

We now need to click the blue Download MSFS PLN button. After that, the Microsoft Flight Simulator flight plan PLN file will be downloaded onto your disk, most probably into C:\Users\YourUserName\Downloads folder.
For convenience, we have moved that file to C:\Flights folder manually as shown on the following screenshot. Note the PLN file was named as departure airfield _ arrival airfield.PLN.

On the next step of this tutorial, we will upload this file into Microsoft Flight Simulator.