Here it says that Moshe arranged the Lechem ha'Panim on the Shulchan. The Sifri says that the Mitzvah began after entering Eretz Yisrael!
Moshav Zekenim #1: Perhaps it is a printing mistake in the Sifri. This requires investigation.
Moshav Zekenim #2: Perhaps Moshe arranged it only on the day of Chanukas ha'Mishkan, 1 for the Shulchan is sanctified only through Lechem ha'Panim (Menachos 49a).
Moshav Zekenim: One opinion in Bechoros 4b says that perhaps Bechoros were not offered in the Midbar, except for the day of Chanukas ha'Mishkan. However, Amora'im argue about whether or not the Lechem was disqualified when they dismantled the Mishkan (Menachos 98a). This shows that it was not only on the first day!