Create a view
Go to: Structure - Views
First we have to create a new view and name it Author List. In the creatation wizard choose Users in the Show dropdown and also select Newest first for sorted by on top. Optionally you can also enter a description, which will help you seperate the different views later. Unselect the options for creating a page or a block.
As usual with panels, click on + Add on top and create a new Content pane. Give the pane an appropriate name, change the Machine Name and select your favorite display format, fields and so on.
To only show the information from the author of a node, you have to add a Contextual filter. Click on add just beside Contextual filters, select This panel_pane (override) on top to only add this filter for this content pane. Check the field User: Uid and confirm with Apply (this display) to change to the configuration.
To be able to define the UID from within the panels, we have to define this in the middle column by the setting Argument input: Edit. Choose the option Input on pane config and give the argument an appropriate label (shown afterwards in the panels configuration).
As last, choose all options you want to be able to override in panels in the dialog Allow settings: Some. Mostly you only need the option Title override here to be able to redefine the title.
Use in Mini panel
Go to: Structure - Panels
A MiniPanel you can use later as a block on your page. To add such one, click on Mini panel on top and give it an appropriate name (Attention, the machine name is generated based on this, which you cannot change later). The description and category is just administration stuff and has no effect at all.
Hint: While you'r creating a Mini panel, you can continue by blicking on Continue, if you are editing one, click onto the wanted section in the breadcrumb.
On the page Context, add the Node as a Required contexts and also a relationship based on User from node (on node.node_author). On both, change the identifier to a human readabe value so you know later on, what exactly the relationship and the context is.
On the page Layout, choose whatever layout you like to use an go forward to the page Content.
As usual on panels, add a new content and choose View panes as category. Choose the above created Content pane and choose the author id for the filter, choose a title and all other values you already know from panels.
After you have designed your panel, save it and add this Mini panel under Structure - Blocks as a normal block.