You can download a client at: https://tox.chat/download.html

Or use your systems package manage:
- Arch: sudo pacman -S qtox
- Gentoo: sudo emerge qtox

Once you have a client add the bot:

Club Cyberia friend ID: 415732B8A549B2A1F9A278B91C649B9E30F07330E8818246375D19E52F927C57F08A44E082F6
Add the bot to get automatically invited to a group chat. Send the bot the message "help" for further commands.