use pocketmine\command\Command I only know some of the use variables like the one above, can anyone give me the whole list and what each one does?
Those things don't just 'do' something. All the use statements you put above your code are (should be) there for a reason. You use the objects, functions and implement functions of them yourself. All the use statements are paths to files in PocketMine: the software you're writing plugins for. That means, that you can easily research the source code and find what does what. (https://github.com/pmmp/PocketMine-MP) Information from this can be found at docs.pocketmine.net as well, but the documentation is quite outdated, making some stuff not correct. For starters this doesn't matter too much though.
You are posting in the wrong section, this section is for help with existing plugins. You can view the Readme/guidelines here, every section has them pinned to the top of the page. The correct place for this thread would have been in the Plugin Development section. Hopefully a staff member can move this thread for you.