Creating a custom map using Tiles

I want to create a map of the tri-state area in the north eastern US for cycling and download it to my Garmin GPS.
I was told to use the ‘Enable manual tile selection’ function so I could highlight the relevant US states, but that option doesn’t appear to be available on the site currently.
Has that functionality disappeared permanently or is it a temporary bug?
If it’s no longer available then to get maps for multiple states do you just have to download one at a time?
Thanks in advance for your help.