Albert Barnes on Hebrews 9:6

When thee things were thus ordained. Thus arranged or appointed. Having shown what the tabernacle was, the apostle proceeds to show what was done in it.

The Priests went always into the first tabernacle. The outer tabernacle, called the holy place. They were not permitted to enter the holy of holies, that being entered only once in a year by the high priest. The holy place was entered every day to make the morning and evening oblation.

Accomplishing the service of God. Performing the acts of worship which God had appointed--burning incense, etc. Lk 1:9.

(b) "Priests" Nu 27:3