You are trying to install the wrong archive. Read the post and follow the instructions https://help.market.envato.com/hc/en-us/articles/202821510-Theme-is-missing-the-style-css-stylesheet-error
Try to install plugins manually, as was previously mentioned.
Elelemntor is a free plugin, that can be download from this page – https://wordpress.org/plugins/elementor/
Let us know if you need any further assistance.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.