Help me connect domain to mailerlite landing page

I have built a landing page need someone to have a call with me to guide me to add my own domain to the mailerlite landing page. I need this done by tomorrow morning.

I have already purchased the domain, have added the domain to mailer lite settings but stick on what next in terms of copying the code and finalising.

Please only apply if you know how to do this and are available tomorrow morning to guide.