TEREZA - How did Joseph Smith translate the Book of Mormon? - I want to know, if he was behind some drape or he was just sitting behind his table, and If Oliver Cowdery could see him and golden plates when thay were translating this book.

JOEL - Little is known about the translation process itself. Few details can be gleaned from comments made by Joseph's scribes and close associates. Only Joseph Smith knew the actual process, and he declined to describe it in public. At a Church conference in 1831, Hyrum Smith invited the Prophet to explain more fully how the Book of Mormon came forth. Joseph Smith responded that "it was not intended to tell the world all the particulars of the coming forth of the Book of Mormon; and…it was not expedient for him to relate these things" (HC 1:220).
As far as we know the only ones who were allowed to see the plates were the 11 witnesses and possibly Emma Smith and a few others.
There are conflicting reports about whether a curtain was placed between Joseph and his scribe. There may have been one while Martin Harris was recording the first 116 pages if Joseph had the plates next to himself while translating. (Book of Mormon Authorship Revisited: The Evidence for Ancient Origens. Noel B. Reynolds).
But David Whitmer, only mentions that a curtain partitioned off an area to keep the scribe and Joseph out of sight of visitors (see David Whitmer Interviews: A Restoration Witness, ed. Lyndon W. Cook, 1991, p. 173, as cited by Neal Maxwell, Ensign, Jan. 1997, p. 40).
Oliver Cowdery's wife said that "Joseph never had a curtain drawn between him and his scribe" and Joseph's wife also said that there was no barrier between her and Joseph when she acted as scribe (as cited by Neal Maxwell, Ensign, Jan. 1997, p. 40). If there was not a curtain between them there might have been some other way that the scribes were prevented from seeing the plates, since at that time no one was permitted to see them. Emma reports that the plates were wrapped up and not directly used during translation, which may have been the case with Whitmer, Cowdery, and Emma, but not Harris. It is possible the common image of a curtain hanging between the Prophet and his scribes, sometimes seen in illustrations in the story of the Book of Mormon, may be based on a misunderstanding. (Cook, David Whitmer Interviews, 173, 233-234, 249.10)