I’ve made a redstone clock and I have a line of redstone that flashes. I want to make a lever which when is activated, allows the redstone clock to function, and when is off, stops its functioning. How do I make such a switch?
You'll need a repeater clock:
Run a lever into the front of a block. Then, on the left of the block, place a sticky piston facing away from the lever, and on the right of the block, place a redstone torch on the block. In the direction of the front of that block, place three redstone next to the redstone torch. Then, connect two repeaters on the left of this dust - the closest repeater to the block should be facing away from the redstone, and the other repeater should be facing towards it. You should also place 1 redstone dust to the left of this second repeater. Finally, attach a different block to the sticky piston.
See the image if instructions are unclear.
This should function as a toggleable clock for most purposes.