How do I add EnderIO to Technic pack?

Solution 1:

To add your own mod to a technic pack (or any technic modpack; official, user or custom), simply go to your pack's folder:

<Technic Installation Folder>/packs/<Pack Name>/minecraft/

And like modpack using Forge-backed mods, simply drag the mod file into the mods folder.

If there are any block conflicts, you will have to change them in the configuration files, found in the config folder in the same folder.

The configuration file for EnderIO (assuming you've launched for the first time) is enderio.cfg.
As for exceptions, you will have to either fix the mod yourself (assuming you have access to the source code) or not use it at all due to things overwriting each other.