1. Open a specific letter, in its title, next to the word "From" click on the sender's address.

2.On the pop-up menu, select "Create a filter" and set the condition move those messages to the folder "Incoming”. 

According to the user's wishes, folder may not filter messages that are marked as spam, but move them to another folder or leave them in the folder "Incoming”. If you want it, disconnected the spam filter.