Before you can do anything (other than watch the blinkenlights) you’ll need to connect your Altair 8800 to your computer via USB. Note: the Altair-Duino is powered immediately upon connecting to USB, the power switch is not used in this configuration.

Step-by-Step:

1. Plug USB cable into computer (the other end should already be connected to the programming port on the Arduino.)
2. Windows 10 should automatically recognize a new serial port.  To check , launch “Device Manager”.
3. Expand “Ports (COM & LPT)” in Device Manager
   
4. Your port should be identified as “Arduino Due Programming Port”.
5. Launch PuTTY (or another terminal program if you choose.)
6. Connect to the indicated COM port at baud rate 115200.
   
7. The front panel lights will flash briefly while it connects.
8. With all switches down, press AUX1 down.
9. On the terminal, you should see a directory of options for front panel switches.

10. Try getting a list of disk images on the SD card.
11. Raise SW12 (all other switches down).
12. Press AUX2 down.
13. On the terminal, you should see a list of disk images.

Now that you’re connected to the Altair-Duino, I’d suggest setting it up so you can Easily Switch Between Serial Devices.