For that bad, rebellious and chutzpadik decision they're condemned to die within a short time, and the Jewish People must wander the wilderness for forty years. Only the next generation will enter the Land.
Next comes Korach. Korach is from the the tribe of Levy. Now, Levy is the tribe that Gd appointed to be in charge of the spiritual needs of the Jewish People. One branch of the tribe was appointed by Gd to be the Priests, and other branches were given specific jobs to do in the Mishkan, Tabernacle and later the Holy Temple.
Korach isn't a "happy camper." He's obviously jealous of cousins who are priests, especially Moses.
By blaming Moses and Aaron, Korach is distorting/denying the divinity of Judaism.
Numbers Chapter 16
In Korach's rebellion he gathers others dissatisfied with their roles, but soon they are defeated.
Bamidbar - Numbers - Chapter 3
10You shall appoint Aaron and his sons, and they shall keep their kehunah; any outsider [non kohen] who approaches shall be put to death. יוְאֶת־אַֽהֲרֹ֤ן וְאֶת־בָּנָיו֙ תִּפְקֹ֔ד וְשָֽׁמְר֖וּ אֶת־כְּהֻנָּתָ֑ם וְהַזָּ֥ר הַקָּרֵ֖ב יוּמָֽת:
We must remember that Judaism is from Gd, and we don't have the authority to make changes. It's not a club.