Insert Minecraft modpacks?

I have minecraft and would like to install Hexxit, attack of the b team and tektopia how do I install many modpacks at once?

You mean they all run in one at the same time? Probably not at all because many mods do not get along and if your computer does not take part.

If you only want to install them and switch between the packs, you should get an alternative launcher such as Curse / Twitch or MultiMC. You can install most packs there.