וְנָ֣תַתָּ֔ה אֵ֖ת מִזְבַּ֣ח הָעֹלָ֑ה לִפְנֵ֕י פֶּ֖תַח מִשְׁכַּ֥ן אֹֽהֶל־מוֹעֵֽד׃
E porás o altar do holocausto à entrada do Mishcan, a Tenda do Encontro.
Rabbeinu Bahya
ובין המזבח, “and between the altar.” Rashi writes that the altar mentioned in this verse is the copper altar outside the Sanctuary. Accordingly, this basin was positioned slightly to the left of the entrance to the Sanctuary so as not to block it but at the same time between the west side of the altar and the Sanctuary. There was nothing blocking the view from the altar to the entrance of the Sanctuary. This is made plainer in 40,6. The whole subject is discussed in Zevachim 59. The basin itself had 12 spouts (like the teats on the udder of a cow) so that the 12 priests who were on duty when performing the daily communal offering could wash their hands from it simultaneously (Yuma 37). [These details referred to the Temple, not the Tabernacle in the desert when there were not yet 12 priests altogether. Ed.] Actually, there were a total of 13 priests involved in the daily communal offering as the Mishnah lists 13 different tasks being performed by these priests (Yuma 25). However, seeing that from a ritual point of view the actual slaughtering of the sheep could be performed by a non-priest, only 12 priests were actually required for the service under discussion. Even a priest did not need to wash his hands and feet prior to slaughtering the sacrificial animal.
Rashi
ובין המזבח BETWEEN [THE APPOINTED TENT AND] THE ALTAR — the altar of burnt offering of which it is written, (Exodus 40:6) that is was to be set “before the entrance of the dwelling of the appointed tent”. The laver was drawn a little to the side and stood facing the open space which was between the altar and the Tabernacle, and it did not stand between them at all because it is stated (Exodus 40:29) “and he put the altar of burnt offering by the entrance of the dwelling of the appointed tent” which implies that the altar was in front of the entrance of the appointed tent, but that the laver was not in front of the entrance of the appointed tent. How was it arranged? It was drawn a little towards the south. Thus is it stated in Treatise Zevachim 59a.