Rashi on Numbers 10:28/רש"י על במדבר י׳:כ״ח

1אלה מסעי means: This is the order, of their journeyings (i.e. these words do not mean, “these are the stations”, as the introductory words of chapter Numbers 33:1, where the names of the stations are enumerated; here Scripture merely intends to state that this was the order which they had to keep when journeying).

2ויסעו AND THEY JOURNEYED means, on the very same day mentioned at the beginning of the chapter did they set off.