Blender’s Bevel tool is used to create chamfers or fillets from the edges of a mesh. You can either use it via the toolbar or by pressing the hotkey Ctrl B.

Edge Slide is great for moving an edge along the direction of the surrounding edges. The fastest way to get to it is by pressing G for grab and then immediately pressing G again to toggle a slide. You can also slide vertices using the same method.

Loops, paths of connected edges, are one of the core concepts in 3D modeling. To select a loop, use the hotkey Alt LMB. If you’re using the Emulate 3 Button Mouse option, double click on an edge instead. To add a new edge loop, use the hotkey Ctrl R and hover your mouse over an edge that runs perpendicular to the path you want the new loop to take.