I want to migrate my theme to a new domain

I tried to migrate the theme from the existing domain (misstoma.com) to the new one (zdravljeistil.com) where I want to use it in the future, but I was unsuccessful. Currently, my theme is not registered on the existing domain, and I don’t know how to register it on the new one. WordPress and the database have been copied to the new server on the zdravljeistil.com domain, but when I try to open the zdravljeistil.com page in the browser, it redirects to misstoma.com instead the other way around. I’m stuck and I need your help step by step to migrate the theme, style and layout to the new domain.

Also, now my live website is no longer working. I can`t Access to my wordpress admin panel anymore. Please help me fix the situation.

Access to my existing domain misstoma.com wordpress dashboard gained.