The battle of Fort Henry began when Grant landed his division on two sides of the fort.
One on the low lying hills of Kentucky to attack, and one on a ridge on the Tennesse side.
Eventually, this would ensure the Forts fall, The Union won the battle after Confederate soldiers failed to bombard the Union Soldiers to prevent the forts fall. This opened up Union shipping as far South as Muscle Shoals Alabama. This would eventually lead to the battle of Fort Donelson, where a Confederate General and 2000 Confederate Soldiers slipped awy. This left the other General to surrender at a nearby cabin by Fort Donelson.
When asked for terms Grant said " nothing but an immediate unconditional surrender can be accepted " earning him the nickname 'Unconditional Surrender Grant'