On Yom Kippur, in the first Temple, the High Priest placed the fire pan between the two staves of the Aron as it says in the Mishnah Yoma 5 (1) .
The outer curtain was looped on the south side and the inner curtain on the north side. He walked along between them until he reached the north side. When he reached the north side he turned around to the south and went on along the curtain, to his left, until he reached the Ark. When he reached the Ark he put the coal-pan between the two poles.
The two staves touched the Peroches as it says here
הבדים היו מדויקים באורך קודש הקודשים, ונראו מבחוץ כמין שתי בליטות על הפרוכת
The staves were exactly the length of the Holy of Holies and appeared from the outside like two protrusions on the Peroches.
My question is: how did the High Priest reach the position between the staves in the first Temple? Did he step over them or under them or …