A: Hey MarcLaCleaer,

Sorry for replying so late, somehow missed this.

You will have to add your Google Search Json API key in this URL
https://app.backlinkchecker.info/backlink/user-api-keys

Check this video out on how to add an API key
https://www.loom.com/share/227ba769e5704d86929a3ac7c412e446

You can get it for free from Google, it allows you to check 100 links per day for free.
You are allowed to add multiple API keys in Backlink checker to meet your goals.
The limit is in the total number of links that can be added.

Also, you will have to mark a list as Check for Indexing at the time of creating it, or you can change the index checking status in the list view.

I hope I was able to answer your queries.