Why does the Torah refer to the Kesavos (posts) as "K'sos ha'Nasech"?
Rashi: "Nasech" is a Lashon of 'Masach' (cover or screen), because they screened the Lechem ha'Panim. 1
Where exactly were the loavs placed?
Why was the top cover (apart from that of the Tachash-skin, which was only to protect the Keilim from the rain) of the Shulchan made of Tola'as Shani (crimson wool), those of the Aron and the Mizbe'ach ha'Zahav, of Techeiles and that of the Mizbe'ach ha'Olah of purple wool?
Ramban: The top cover of the Shulchan, which symbolizes Keser Malchus, which in turn, represents Midas ha'Din, was made of Tola'as Shani, which is a shade of red, which also represents Midas ha'Din; whereas the Aron and the Mizbe'ach ha'Zahav, which symbolize the Midah which incorporates all the Midos, was covered by a Beged Techeiles, which represents all the Midos, 1 and the Mizbe'ach, ha'Olah, on which the blood is sprinkled that atones for the soul, was made of purple - which is a deeper red.
As hinted in the word 'Techeiles'.