forgot to mention this oops
please use the gilded games util mod from i think june 1 2016 to be able to run aether 2 gotv

https://www.curseforge.com/minecraft/mc-mods/projecte-aether-addon
https://www.curseforge.com/minecraft/mc-mods/skylands-utilities

https://www.curseforge.com/minecraft/mc-mods/aether-addon
https://www.curseforge.com/minecraft/mc-mods/aether-lost-content
https://www.curseforge.com/minecraft/mc-mods/aeble
https://www.curseforge.com/minecraft/mc-mods/tinkers-aether
https://www.curseforge.com/minecraft/mc-mods/aether-additions
https://www.curseforge.com/minecraft/mc-mods/aether-aspects
https://www.curseforge.com/minecraft/mc-mods/extra-moas
https://www.curseforge.com/minecraft/mc-mods/omnis-aged-aether-blocks

Aether 2 is a continuation of the Aether, happening years after the original Aether. It has more mobs, trees, plants, blocks, etc. Yet has no dungeons yet, and is not complete. When it is complete though, it'll certainly be better than Aether Legacy. Take a moment to check it out and support the creators. It's an amazing mod.

Aether legacy is a port of the Aether for beta 1.7.3 (The original mod.)
It has much less content than Aether 2, but both mods can be used at the same time, and Aether Legacy (As of the creation of this blog) has all 3 dungeons, while Aether 2 is not yet complete, and has none.
Download link: https://www.curseforge.com/minecraft/mc-mods/the-aether

This one is much simpler and less convoluted, which is why i recommend you use MultiMC if you love modded Minecraft. Select the Minecraft version compatible with the Aether version you want to download. Select your instance then go to "Edit Instance". once you did that, click "Install Forge" and install the latest version. Now all you need to do is go to "Loader mods" and click on "Add" then select your jar.

Both Aether Legacy and Aether 2 are found in curseforge on the mods section. The installation is fairly simple. You'll have to have the respective version of minecraft for the Aether 2/Aether Legacy version you're installing. Once you have both of these things, download Minecraft Forge's latest version on your selected Minecraft version, then install it. Once you are done with that, put the Aether .jar into the mods folder located in your .minecraft.