Open Premiere.

(in this wiki we're using version 10.3.0)

Create a new project if you haven't already.

Name your project.

And Browse to a place you'd like your project to be saved...like your external hard drive.

Under the Scratch Disk tab, if you have every dropdown as "Same as Project"

you should be fine.

Click OK

Once you've created your project

choose File > Import...

or

Command + I

Navigate to your A7Sii or any other types of HD to 4K native camera footage clips
It's easier to select the MP4 files if you sort by kind, by clicking on the word "kind" in the kind column

Highlight the clips you want

click Import

Drag your clips to the timeline and start editing.