Yeah, unlike the SV you have to hook up a computer to the D-180 to do the software update. The process is a bit scary the first time you do it, and it has been several years since I did it but here are a couple of tips that I remember.
I used my old WinXP laptop and it works fine for this. You have to have the Dynon Support Program loaded on the laptop and you should use the Dynon dongle with the blue connectors, if you have that.
In this picture I was running my D-180 on the bench when I first got it way back in 2009. Geez, I can't believe that was 10 years ago already!
The dongle is short so I used an extension serial cable so I could put the laptop on the wing while doing the updates after the unit was in the airplane. Also be sure to have that old laptop connected to a charger. If the laptop battery dies during the update you probably will have to send the D-180/100 to Dynon. Stuff can happen, that is why the advice to photograph your settings. My file of those settings has 43 photos in it, not hundreds.
I don't remember if you have to update both the D-180 and the D-100 for them to work together but it's probably a good idea. I know only the D-180 has EMS and the D-100 gets the data from it so it may be that you don't need to do them both to see the EMS updates you are looking for but I would plan to do them both. I know the with the SV and two screens you have to do them both or they don't work with each other.
You are already ahead because you have been reading the documentation. It should go smoothly with the D-180. However when I first updated the D-100, the support program wanted to know if I had a magnetometer. I answered yes, since I did have a magnetometer and then the D-100 froze up. I had to call Dynon. The issue was that although there is the one magnetometer in the system you do not have a second magnetometer for the D-100. So the correct answer to that question is NO for the D-100 update.
I would not do the updates on a weekend. Do them on a weekday when you can get phone support if needed. If you shut down the update process without it completing you will probably brick the unit and have to send it in.