Connecting ArcMap to secure folder

I am accessing data from a National Data Services secure server. Within the server, all my project data is in one folder, and applications like ArcMap are in a separate folder.

In ArcMap, "add data" will connect to the drive (M:), but the secure folder is not listed as being there.

I had a similar problem with accessing Stata commands, and that was solved by adding "adopath +" at the beginning of every do file, to specify the directory were the commands are listed.

I think I need to direct ArcMap to this secure folder, in a more technical way, than just using "add data", but I have no idea how, I can’t find the answer online, and technical support at the data service has provided no assistance.

As it’s a secure server, I cannot add snapshots of the problem here.