Tutorial: How to use slash commands - jh220de/ccbot GitHub Wiki
Hey, this is how you can.. well, clear a chat!
1. Inviting the bot
Click on this link (http://jh220.de/ccbot) and follow the instructions. You may select a server to invite the bot to.
After that, it should look something like this (see below).
Press Continue and Authorize.

You're done.. for now. This only needs to be once!
2. Using commands
Go into a channel the bot has permission the to view, and type /clear (don't press enter yet).
If everything works, the command info will pop up:

Press Tab or click the command to view more options:

Now, specify options by pressing Tab or clicking on an argument:

Press enter to confirm the command.
There's more commands. Go check 'em out: https://github.com/JH220/discord-clearchatbot/wiki/Command-documentation
Legacy
Alternatively, you can use the deprecated cc clear command by just typing it directly in the chat (without a /).