Now the main point of what we are saying is this: We have this kind of high priest. He sat down at the right side of the throne of the majesty in the heavens.
References for Hebrews 8:1
He's serving as a priest in the holy place, which is the true meeting tent that God, not any human being, set up.
Every high priest is appointed to offer gifts and sacrifices. So it's necessary for this high priest also to have something to offer.
If he was located on earth, he wouldn't be a priest because there are already others who offer gifts based on the Law.
They serve in a place that is a copy and shadow of the heavenly meeting tent. This is indicated when Moses was warned by God when he was about to set up the meeting tent: See that you follow the pattern that I showed you on the mountain in every detail.
References for Hebrews 8:5
But now, Jesus has received a superior priestly service just as he arranged a better covenant that is enacted with better promises.