These farms are class specific but can be done with class trials. You can only play a class trial for three hours, so before you have to remember to mail any gold or items before that. When your three hours have gone, simply make a new character. Many of these farms are very good if you can park a character at the farm, log in, farm a while, then come back and farm more at a later time.
A lot of people ask about good routes to farm when doing these professions, but there really are no special routes to run. If a route is posted online then that area will quickly be overpopulated with people gathering. The best way to go about it is to get the Gathermate addon and spend a few hours gathering all over the zone. You will then get aquainted with the entire zone and where the different herbs or ore spawn, and you will get severel of your own routes you can take depending on if there are other players competing with you for the nodes.
I'm just now coming back to WOW and TSM after a long time and boy has this incredible addon changed! Right now I'm leveling all expansion version of inscriptions so I'm able to craft all the illusions. I created an All Herb group from this import ( https://www.tradeskillmaster.com/group-maker/ogth3m9d ) but when I search this group in the shopping tab you see it is searching all items (Scanning x/120 in the status). However, only BFA herbs are shown. I verified that this group is using the default, stock shopping operation and validated that operation was indeed stock. What am I doing wrong?