When clicking on a Knowledge Article in the Object Matching panel at the right-hand side of the screen, the pop-up windows has 2 push-button options: "Link" and "Link and "Resolve":
This article has the information on other push-buttons can be added.
To add a new button go to the Configure Application-->Automation Tools-->Object Matching Lists.
Select the appropriate Matching List that is associated with the Layout. e.g. Incident ObjectMatching
Click on "Edit Preview" beside Knowledge:
Click on "Edit Preview" besides the Type of Knowledge article (it will need to added for each Knowledge article type):
At the bottom left there is a "Add New Button" link:
This brings up the Add New Button dialog:
This new button will be shown on the pop-up window.