You have a Celo node running. Commands will connect to a Celo node to execute most functionality. See the Running a Full Node instructions for more details on running a full node.
The Celo CLI is published as a node module on NPM. Assuming you have npm installed, you can install the Celo CLI using the following command:
npm install -g @celo/celocli
The tool is broken down into modules and commands with the following pattern:
celocli <module>:<command> <...args> <...flags?>
celocli tool assumes that users are running a node which they have access to signing transactions on. See documentation on the config module for information about how set which node commands are sent to.