How to dial out with ARI

I’m fairly new to asterisk and ARI but picking things up pretty fast - but I’m completely lost on outbound calling (inbound I have achieved, ARI application is handling the calls etc).

To test, I have set up an outbound sip trunk with orbtalk…
From the stasis application I am trying to originate a call through this using…

endpoint: SIP/[user]:[pass][did]
app: “TestApp”

This just seems to be failing, the channel state is “Down”…although I’m not too surprised by this as I’ve literally just thrown something together to see if it works!

Am I even vaguely on the right track?

That’s how you do it. What’s the complete output? Can you call out normally via SIP using that dial string?

I worked out what this was - this one had to be set up as an outbound trunk, which can be used in the connection string. Sigh