I'm sorry, but it is unclear from your post what does not work (setup of the free link OR a link that is the result of this button on the frontend) and where (content view, search view etc). Please give us more details.

Sorry Klas, I mean in the administrative panel, when I create the List&Search. The "+" in the red circle doesn't work...it doesn't open the pop-up where I can choose a specific Form.

I hope this topic is more clear...

PS: you can see this in the "Building a Front-end Manager" video at 10:00.

Which version of Seblod do you use? Try installing latest version again if you are already on 3.10

What kind of error do you get when you click on + (you will need to have Firebug on Firefox or developer tools on Chrome active to see any errors) ?