Creating new content (tables) through other tables
The recommended way to install SMW is with composer, yes. The second best (I hope it is still working) is with git, although it will not take care of the dependencies. Downloading tarball will make upgrading difficult.
Composer is the recommended installation method (this is to ensure that dependencies as specified are loaded and not added by random selection or version).
I would not recommend git unless you are a developer or know what you are doing (if we change dependencies then this will have to be taken care of by the user him(her)self, and we do change dependencies).
Tarball is another option but if a new release occurred then you need to replace files in the extension and vendor directory to update all dependencies deployed by the new tarball.
