To rekindle a fire from hot coals, rake the charcoal towards the front of the firebox where the combustion air (secondary air) enters. Place the pieces of wood on and behind the coals. Open the air intakes fully and leave them open until the pieces of wood are well-charred.
Allow the fire to burn with bright turbulent flames until the wood is burning well. This should take about 20 to 30 minutes, depending on the size of the pieces and the moisture content of the wood. If the appliance is catalytic, this will also be ample time for the catalytic combustor to light-off. Now the by-pass can be closed and the air intakes regulated for a nice even burning fire.
Be sure to read the stove's operating manual for complete instructions.