Like with most things in life, the question of whether it's hard to use a blowtorch is relative. Compared to the way blacksmiths use to weld in the Middle Ages, a blowtorch is a snap to use. But compared to flicking on a lighter, a blowtorch is a little tricky. Plus, blowtorches need to reach very high temperatures to be able to mold and cut metal; that means there are some dangers involved in blowtorch use, too.
To use a blowtorch, you first have to familiarize yourself with its parts. A regulator controls the flow of the gas, hoses connect steel cylinders to the actual torch part of the blowtorch and the torch head has two valves to control the flow of oxygen and gas. The tip of the torch head can be switched according to what type of job you're doing and what kind of gas you're using. An igniter is the part of the blowtorch that actually lights the flame.
Once you have blowtorch anatomy down pat, you can suit up in your protective gear and turn on the torch with a multi-step process. First you adjust the pressure of the gas by opening the cylinder gradually to let the acetylene flow. Then you open the valve on the torch head to get the acetylene at the proper pressure. Once you've found it, close the valve so that you can follow the same process with the oxygen. After you've achieved the right oxygen pressure, close the valve on the torch head. Then you have to double check that there are no leaks in the hoses or valves. Open the acetylene needle valve and ignite the torch. Once the black smoke stops, open the oxygen valve [Source: Oregon State University] and start welding. It may sound complicated, but once you learn the ropes, it's not that bad.