Perfect install on my 2018 Lusso this morning. Highly recommended.
I followed the instructions on Ameridan's blog. The whole process took 3 minutes, total, including the system acquiring the satellites.
Quick summary: With the car off, open the SD card cover by pressing down and out on the little notch. Put the nav card in, label side up, unlocked. Turn on the car, and select Navigation from the menu. It should load right up.