The Cobb is simple to light, here are 2 ways:
The Cobblestone: The Cobblestone uses a rapid ignition technology. All you have to do is hold a flame to it for 20 seconds and then place it back into the fire grid once it starts self-igniting off the flame (should you have any issues with the Cobblestone due to them being very old then use a thumb-nail sized piece of firelighter in the base under the Fire Basket and this will have the Cobblestone alight in seconds).
Briquettes/Charcoal: Use 2 or three small pieces of firelighter, placed on the base under the Fire Grid. Ignite these and place the Fire Grid, with your briquettes/charcoal in it, over the lit firelighters.