Well then the dll should be located in your OpenSSL installation's root directory so just copy it to the servers folder ["c:\Program Files\OpenSSL-Win64" for me]



You can also access command prompt by typing 'cmd' in windows search.

Given that I don't actually have this server it's hard to diagnose, if you already have MySQL installed and the server has it's own stand alone version they will conflict with each other [ie if you didn't manually install the database yourself].
In which case you need to type 'services.msc' in the windows search, find MySQL in the list, right click and choose stop. Then attempt to run it and see what happens. Otherwise I recommend googling something along the lines of 'MySQL error 1067' given that the solution may vary depending upon your circumstances.