After installing the MAZDA TOOLBOX software, if you have the SD card type (mine is MZD TYPE), you download the Mazda software and insert your card into your PC.
I only have a 3mb connection, so downloading took several hours.
It will then guide you through the process of updating. On my 2019 version, it's supposed to be updated twice a year; the last update was in February, so it's long overdue:(
The cards with the most recent maps can be purchased from the dealer or eBay; determine which is more affordable!