Solr works with a set of multiple configuration files.
Each Solr configuration file, has it's own purpose.
Therefore, in some cases, some publishers (CMS systems, etc), will chose to create their own structure for such Solr configuration files, such as, it is the case with Drupal, and maybe WordPress (WPSOLR), and others.
When uploading your solr configuration files, using your Opensolr Index Control Panel, it is, therefore, important to upload your files in a specific order:
So, basically, you should simply create those 3 archives and upload them separately, in this exact order, and then everything should work.
You can, of course automate this, by using the Automation REST API to upload your config files.