Then you need something to hold the helium so that it won't float away. Something light, such as a balloon, is best. The large airships of the past used many giant airtight bags inside the rigid frame and then covered the outside with canvas. So you won't float too high, you need weights on the airship. The weights are called ballast.
Water is used most often.
When you want to rise from the ground, you drain some water out. When you want to come back to the ground, you release some helium. To steer to the left or right, you need flaps called rudders. To steer up and down, you use flaps called elevators. Some blimps have engines that can rotate in different directions to help steer.