About the “site” field: plugin will not work on subdomains if you enter your main site url.
Example: if you enter example.com, plugin will work on example.com, www.example.com and example.com/contest but not on contest.example.com.
[This does not apply for a multisite package.]
After the payment you will receive the plugin download link and instructions within a few minutes.
In the case of purchase a multisite license, your order will be processed manually at working hours (Mon-Fri: 10am-8pm UTC+2, Sat-Sun 10am-6pm UTC+2).
For any problem or question, send me a message at firstname.lastname@example.org