Looking Around
Use the arrow (cursor) keys to scroll around the map, or alternatively, drag the map display in the top right with the left mouse button.

Selection
Click on one of your units or drag over a group of your units with the left mouse button. You cannot select enemy or passive units.

Move Mode
Press 'M', or click 'Move' on the console to the right. Any selected units will move to wherever you subsequently left-click.

Attack Mode
Press 'A', or click 'Attack' on the console to the right. Left-click on an enemy unit or on the terrain. If you fire at a unit, your units will try to pursue it until it is destroyed. If you attack the terrain, your units will only fire three rounds per order.

There are more advanced controls, but these should be enough to get you going.