Before placing your Tri Tip on your Traeger grill get the fire established which takes around 5 minutes and then preheat the Traeger grill to 180 F and close the lid on the Grill.
Leave the lid closed on the Traeger grill for around 15 minutes and during that time prepare your Tri Tip by rubbing it with coffee grounds and Beef rub if you want too.
This gives it a better flavor however you can skip this step if you want too.
Then to cook the Tri Tip on the Traeger grill place the Tri Tip directly on the rack of the Traeger grill and let it cook at 180 F for 3 hours.
So in short terms. It takes 3 hours to fully cook Tri Tip on a Traeger grill so be patient.