A command is a one or more words (or letters) that you can type in chat, beginning with a slash. When doing so, it executes one or more chained actions.
How to make a command
Command: The name of the command. For example, in order to create command executed using /weather, you must only put the first word: weather, without /.
When command executed: The procedure with the actions of the command when it will be executed.
Usage of commands
You can use the "command parameter with index x" procedure for parameters to work. Doing such would allow you to get a value from the parameters following the main command.