Creating external extension

I have a mobile connection to server, all registered ok
FreePBX is also connected and working

My problem is I want route to mobile from FreePBX

ie when on vacation have IVR or extension 1111 go to mobile (using Zoiper)

Sadly I’ve tried for days to bridge the gap from my local ran FreePBX system to the voip Zoiper mobile without success…

If you don’t already have a trunk on the PBX, create one, using a unique subaccount

With an extension number assigned to the mobile subaccount, and suitable Outbound Route pattern, you should be able to dial the mobile from the PBX.

For the IVR case, set up a Misc Destination. For an extension, use Follow Me.

I have a sub account that the mobile is connected to and have Zoiper running and registered on voipms
Do I need to give it an extension number on voipms definition?
I tried creating a custom extension 1001 on freepbx with advanced edit extension dial set to sip:[email protected]
Set a inbound route to priority send my other mobile number to ext 1001

I get “user busy”
I know I’m missing something simple but I’ve read so much I’m losing the plot and don’t know where to look…

So doing more testing
The Zoiper app can make calls out via voipms
It can call itself with the assigned extension 1002
However I can’t seem to figure out how to call it from within freepbx , when I add sip dial info in advanced edit call edit on freepbx I get the ring tone but it doesn’t ring via app
Sorry I know it’s probably something silly my head has missed or perhaps I’m missing a setting

Is there an example of how to define an extension in freepbx that routes or calls an external sip?

My head hurts