Use an audio cable to connect the headphone jack of this computer to the cassette jack of a TRS-80 machine.

Boot into Basic (answering to the “Cass?” question), run the SYSTEM command, type , press Enter, then start audio playback below. When playback ends, type / then press Enter.

You may have to adjust the volume below or on your computer to get the TRS-80 to properly load the program.