I am currently studying Meshechet Barachot and have two related questions: 1) What Bracha was said over the manna during our forty years and was a Shehecheyanu said the first time it was eaten? 2) If we say Boray Peree Ha’etz over olives and olive oil (after squeezing), why do we say Ha’etz over oranges but Sh’hakol over orange juice (squeezed)?

1. I don't know if the Jews in the desert recited Berachot before eating food. The text of Berachot was established by Ezra and Anshei Keneset Hagedolah. The Gemorah does say (as you know) that Moshe established the first Beracha of Birkat Hamazon for the Man, so it would seem to come under the category of Lechem (bread). The Rama of Panov wrote the in Messianic times we will eat from the meal of the Leviathan and there will be Man on which we shall bless "Hamotzei Lechem Min Hashamayim".