Hi Amit,
Thanks for your reply! I understand if my description is not crystal clear but the video is. But since then I could solve my issue. Please check my site (servio.hu) and you can see it yourself. If you click on the English flag itt will take you to an English page, and that English page has a different menu (in the upper part of the webpage) than in the Hungarian one.
It turned out that I do not even have to use plugins, because OceanWP knows this by default.. I had to select the corresponding menu in the Page settings under Menu – Main Navigation Menu.
Case solved.
Thanks again.
