AnubisBot uses libraries which utilize some newer PHP stuff. Thus, you need a newer version of PHP (Sorry, but only PHP 7+ is supported because it's the only one DiscordPHP works with).
AnubisBot utilizes Composer, so you'll need it.
To create a new project for AnubisBot, execute the following:
$ composer create-project pazuzu156/anubisbot --prefer-dist
If you want the latest code base, use
dev-develop is the development branch, and thus is considered unstable. Only use it if you're fine with things breaking all the time ;)
$ composer create-project pazuzu156/anubisbot:dev-develop --stability=dev --prefer-dist
From here, you should be set to running the default bot with all the built in commands. To run, execute the following:
$ php cli run