I have made two easy programs for gathering by several characters at the same time (multiboxing).
1. Levelbuddy.
Simple (15 minutes setup) but powerful. It uses input broadcasting so currently, it's against ToS.
Levelbuddy WoW Multiboxing Software - Official Site
2. Wow Switcher.
Simple switcher for WoW windows. The most useful for gathering (mining, herbalism). Doesn't use broadcasting so it is legal in terms of ToS!
Wow Switcher - Legal Multiboxing Software
Ask any questions or request features there or in our discord.