The first leg in Iceland on Tuesday night will be the Scottish champions' first competitive match of the season and new manager Ronny Deila's first competitive match since taking over from Neil Lennon.
Before flying out from Glasgow airport on Monday morning, Collins confirmed winger James Forrest is out with a groin problem to join injured skipper Scott Brown on the sidelines, then turned his attention to the crucial qualifier.
He said: "Of course it is a big test but we are looking forward to it.
"That's three weeks that we have been back now, this is the big one.
"All the preparations have gone towards getting a good performance and good result.
"We have had four (pre-season) matches and the squad is getting fitter every day.
"We want to go there and try to score goals.
"We have watched them twice, we have had videos cut up so we know their strengths and weaknesses but at the end of the day it is about how we play.
"This is where Celtic want to be, we want to be on the big stage.
"We know we have to take care of this team, it won't be easy, it never is at the start of the season but we are looking forward to it."
On the absence of Brown and Forrest, the former Hibernian manager said: "It is obviously disappointing, two big players, certainly Scott our captain and leader, but we have to get on with it now.
"We have lots of other good players in the squad who have to step up and show that they can do a job for the team as well and I have no doubt they will."