Both myself and other people have written threads on how to join a multiplayer session. I,ll give you a quick rundown. You have TS12 and registered it which meets the first two requirements. Do you have Direct X 9 which is what Trainz runs on. It will sit on your computer quite happpily with a more recent version and should be downloaded from these forums. Now the million dollar question, "Do you have the Steam version of TS12". If the answer is no that is good. If the answer is Yes that is not good at all although N3V Games may save the day. Let us know the answer. The Next thing you need is Build 49922 (see Launchpad). If you don,t get the patch(es) from these forums. Now all you need is a multiplayer session to join,lol. You should download the Following; USA PROTOTYPE MULTIPLAYER v3 by Danny (Route & Session). Montana Rail Link MP 2.8 by Jib 228, route & session. UMR 2013 SUMMER MULTIPLAYER SESSION version 3.1 by Lewis and UMR 2013 SUMMER MULTIPLAYER by Neilsmith 749 (route). I won,t give you my session as It is broken and I,m currently fixing it but it should be on the DLS in a few days. These are among the most popular MP sessions and they are sometimes up 24/7, UMR in particular. Danny is the main host for USA, myself or Jib228 for Montana Railink. After you have downloaded each route and session check for missing dependencies and download any that are missing. Teamspeak 3 is pretty useful or even mandatory in the case of UMR as you have to ask for the password in Teamspeak. I think that will do for now. Feel free to ask for further help. It is very important that you only download content from the DLS in Content Manager. Buying payware from any source, including Planet Auran, or downloading Freeware from a 3rd party site could wreck a multiplayer session. The multiplayer copy of TS12 MUST be a "clean copy" to prevent problems joining a session.