First of all, for the uninitiated, the designation DLS stands for Download Station, the central server where Auran stores all the Assets that have been created and submitted by Trainzers for general distribution to the Trainz Community. If you have a Trainz User ID and password you can access this site and download assets into your copy of Trainz.
Users of TRS2006 or above can use the supplied Content Manager Plus (CMP) application that manages content, searches and downloads. CMP also works hand-in-hand with CCP to aid in content creation.
FCT stands for First Class Ticket. For a nominal sum you can purchase a First Class Ticket from Auran which will allow you unlimited download privileges. Without the FCT, you are restricted to 100 MB each day and a download speed of 4kb/s. Depending on the copy that you purchase, you may be supplied with a '1 month FCT' free of charge with your new software.