Guild Wars 2

So my sis is making it, she needs this archivement in Verdant Brink
to get ‘Verdant Brink Tiger Refuge Sign’
It said you can obtain the item from finishing the Meta event in Ordnance Corps outpost
But when she finished it, nothing happen, so we have no idea anymore
pls help T-T

Thank you very much ^^

I’m new here ^^ So…I wanna know if I need to finish the main story before I can do Heart of Thorns when It comes out ^^ Thank you kindly for any answer.