Count enable vs Clock enable

This may be a stupid question :confused: but I'm having a hard time with it. every time I think I get it I get confused again. can someone please explaing this? what happens with lets say a simple counter if it has a count enable, or a clock enable?

help! I'm trying to create a pulse with the FPGA starter kit, but i want an outside signal to control whether the pulse will be created or not.