For Basic Authentication, you can simply type your Github username and password.

Steps

Click '+' button next to 'Data Frames' and select 'Import Cloud Apps Data'.

Click 'Github Issues'.

Create connection from here if you don't have.

Select "GitHub Issues".

Type connection name, Github username and password. Then, "Add" button.

Type Owner and Repository and click "Get Data". If the preview is okay, click "Import".

Repository Owner and Repository Name are something like below. (just in case!)