Yeah, Trial Accounts can't use AE as far as I know.
Trial Account Restrictions
Unfortunately, it does seem like trial accounts are not able to start or create Mission Architect missions by themselves.
There are quite a lot of restrictions on trial accounts that can be annoying to players who actually want to try out the game (no tells, fer example), but we also faced a huge influx of gold (influence) spammers who were using these trial accounts to disrupt everyone's gameplay experience, hence the steps to curb this.
My best suggestion, since you can't use any global channels on a trial account is to use the help channel. "/hc <message>" Explain your trial account status, and ask for someone helpful to show you some of the good mission architect arcs.
Sitting around in one of the AE buildings speaking in local might work, but that's just going to get you swept up in the latest craze of farm teams. Not exactly much story in those arcs. And not much point if you're restricted to progressing past lvl 14, hey? 
For actual arc creation, you're going to have to pony up some cash, alas. This is probably because they didn't want people publishing arcs from trial accounts. You can see a bit of the UI from the issue 14 trailer if you're just interested in seeing how it looks.
Invictus Est Level 50 Invul/Fire Tank
Malentis Level 50 Ice/Energy/Leviathan Dom (Freedom)
Black Jeremiah Level 50 Fire/Fire/Mu Dom
Sejanna Level 50 Dark/Dark/Elec Def (Virtue)
Arc #119664 - The MiniMech Cometh - Hess TF Mini-Sequel
Thanks for the help guys. I kind of figured they wouldn't let trial accounts use the AE buildings too much, but that's ok. It seems like a lot of people do enjoy creating their own story arcs so I'm guessing that it's probably worth it.
I don't know if this is supposed to happen or not, but I got a trial account because I'm curious about the Mission Architect and if it's anything new. But the problem is I can't use the terminals inside the AE buildings. It shows the hand that says you can use it, but when I click nothing happens. I'm wondering if trial accounts just can't use them, or if there's some problem.