Most of the functions have associated keyboard shortcuts and can be accessed from the menu.
For example the shortcuts for the default sharing options can be found under Article / Share.

Tab: Move the focus: Sidebar - Article List - News Reader

Up/down arrow: Step or scroll up/down on the focused section

Left/right arrow: Open/close folders on the sidebar
Category: News, Feedly, Feedbin, RSS
Compatibility: MAC OS X Yosemite, El Capitan
Leaf: News Reader for Mac OS X (Yosemite, El Capitan)

Leaf is an amazing news reader for Mac OS X (Yosemite, El Capitan). Read, share, star and search news from all of your favourite websites by using a clean, intuitive, OS X Yosemite, El Capitan-style next generation interface. Leaf is supported feedly and feedbin. Feedly App for Mac OS X, Feedbin App for Mac OS X