Windows Explorer lets you open archive (tar and tgz) files like any other folder.
In VBA you can easily handle normal files and folders, but opening and indeed creating archive files takes a little more - and that you'll find here.
Callback functions are a hidden gem in Microsoft Access. With these, you can dynamically fill a combobox or listbox entirely from code with a versatility way beyond what a simple static value list can offer. To get started, learn the basics.