USE CHROME. Firefox may fail.

https://discordapp.com/developers/applications/
=> New Application
=> Enter any name for your new bot
=> Click "Bot" in navigation
=> Add Bot
=> Yes
=> Reveal & copy token
=> You can choose "public", but I'm not sure what that's for

Now for the OAuth2 crap.

Click "OAuth2" in navigation
=> Select scope "bot"
=> Permissions: View Channels, Send Messages, Read Message History, Mention Everyone, Add Reactions
=> Copy & open the displayed URL
=> Select server
=> Click "Authorize"
=> I'm not a robot
=> done