1. Once you extracted the script, download the Iperf3 version for you operating system here:
https://iperf.fr/iperf-download.php

2. Extract the Iperf3 files to the same folder as the script.
MAKE SURE THE IPERF3 EXECUTABLE IS SIDE BY SIDE WITH IPERF3 LAUNCH.BAT IN THE FOLDER

3. Execute iperf3 launch.bat

4. (Optional) Change the default settings to your needs

5. Analyse the results in the .log file created