(מא) וְחַגֹּתֶ֤ם אֹתוֹ֙ חַ֣ג לַֽיהוה שִׁבְעַ֥ת יָמִ֖ים בַּשָּׁנָ֑ה חֻקַּ֤ת עוֹלָם֙ לְדֹרֹ֣תֵיכֶ֔ם בַּחֹ֥דֶשׁ הַשְּׁבִיעִ֖י תָּחֹ֥גּוּ אֹתֽוֹ׃ (מב) בַּסֻּכֹּ֥ת תֵּשְׁב֖וּ שִׁבְעַ֣ת יָמִ֑ים כׇּל־הָֽאֶזְרָח֙ בְּיִשְׂרָאֵ֔ל יֵשְׁב֖וּ בַּסֻּכֹּֽת׃ (מג) לְמַ֘עַן֮ יֵדְע֣וּ דֹרֹֽתֵיכֶם֒ כִּ֣י בַסֻּכּ֗וֹת הוֹשַׁ֙בְתִּי֙ אֶת־בְּנֵ֣י יִשְׂרָאֵ֔ל בְּהוֹצִיאִ֥י אוֹתָ֖ם מֵאֶ֣רֶץ מִצְרָ֑יִם אֲנִ֖י יהוה אֱלֹהֵיכֶֽם׃ (מד) וַיְדַבֵּ֣ר מֹשֶׁ֔ה אֶֽת־מֹעֲדֵ֖י יהוה אֶל־בְּנֵ֖י יִשְׂרָאֵֽל׃ {פ}
(41) You shall observe it as a festival of יהוה for seven days in the year; you shall observe it in the seventh month as a law for all time, throughout the ages. (42) You shall live in booths seven days; all citizens in Israel shall live in booths, (43) in order that future generations may know that I made the Israelite people live in booths when I brought them out of the land of Egypt—I, your God יהוה Adonai. (44) So Moses declared to the Israelites the set times of יהוה Adonai.
וַיִּסְע֧וּ בְנֵֽי־יִשְׂרָאֵ֛ל מֵרַעְמְסֵ֖ס סֻכֹּ֑תָה כְּשֵׁשׁ־מֵא֨וֹת אֶ֧לֶף רַגְלִ֛י הַגְּבָרִ֖ים לְבַ֥ד מִטָּֽף׃
The Israelites journeyed from Raamses to Succoth, about six hundred thousand men on foot, aside from children.
This does not mean literally “booths” but, “the clouds of Glory" by which they were sheltered
...Here, at the beginning of the rainy season, a further observance is commanded, in commemoration of the ongoing miracle that was done for them throughout their 40 years in the wilderness. According to the opinion that the phrase refers to actual booths, they did begin making them at the start of the rainy season because of the cold, as people do when they camp, and that is why our text commands that booths be made at this season. In that case, what the future generations are supposed to know is that they made their way in the wilderness and "found no settled place" (Psalms 107:4) for 40 years. But God was with them, and they "lacked nothing" (Deuteronomy 2:7).
So that your generations will know that in Sukkos. ....The commentaries discuss why we were commanded on the 15th of the seventh month, which is the beginning of the cold, rainy season, to leave our permanent dwelling places and stay in a temporary abode. This teaches us that Hashem intended that each Jew should recognize that the honor of his lofty spiritual soul is above the heavens. Its permanent dwelling place is there, and it only came into this world to have a temporary dwelling. The phrase “so that your generations will know” fits well with this explanation, because according to the other explanations it should have said, “so your generations will remember.”...