Hi,

You have two options:

1. Create a new menu item, with Smart Search view, then using Mega Menu add search icon and hide Menu item title. Video guide: https://www.youtube.com/watch?v=iJL3rSqVb1U
2. Publish Search module in "menu" position - remember to add class name: themis-top-search inside module settings.

2nd method was used by default in QuickStart.

OK.

a) The english search cannot provide any results! LINK: https://www.rules-chess-strategies.com/en/search-en

The greek search can provide results normally.

https://ibb.co/pXmjDGG

https://ibb.co/LzC5F60

b) How can i edit the advance search?

Finder (Smart Search) it's Joomla Core Search engine, it's not from template. Don't get me wrong, but the Helix template can only overwrite the appearance, not the mechanism of operation.

Ideas:

• Try to Index content again.
• Then also check Maintenance and Options inside Smart Search component (admin).
• You can ask/search on forum.joomla.org

edit the advance search...

From Menu item settings you can change some options used by Smart Search on front-end.