Mark the outline of your man on a block of ice. This can be done using a notching (scoring stick) or pointed chisel. Don't worry about the details here. The object is to get the basic guidelines down that you will be carving around. Since the block of ice you're working with will likely be square, it will be difficult to draw every aspect of the man. Notch the outline on both sides of your ice block, either by notching the basic outline fully or by notching grooves spaced evenly apart that will lay out the general path you'll carve from.
Chip away the ice around your guidelines with a wide flat chisel and mallet to remove the larger chunks of ice to form the legs, torso, and head. You still won't be applying any details. Remove the chunks of ice by hitting the chisel with the mallet repeatedly with force. Angled strikes work best and will allow you to break the ice free as it loosens. Work front to back to shape the man as you remove the ice.
Cut the details of your man using a pointed chisel. This will allow you to shape the eyes, nose and mouth. Switch to the flat chisel if you need it to form muscle. Since this is ice, the details will only be distinguished as rises and indents in the surface of the sculpture.