https://minehut.com/dashboard/home is the link
after you click the activate server button it will direct you to a new page where you will watch a video and after 30 seconds you can click the continue button, this will take you to your settings page. on the top of the page you'll see a link for console, that is where you can enter the OP command.
full walkthrough here: https://minehut.zendesk.com/hc/en-us/articles/4649921013139-How-do-I-OP-myself-