Homemade level
Nowadays, marking is performed by a water or laser level. But these tools are quite expensive. There are other ways of marking, more affordable in price, so that they will suit everyone. For example, you can use the hydraulic level. This device will help to easily determine the place of mounting the main profile. The hydraulic level can be bought in a store or make it yourself from a regular rubber hose and glass tubes. It is important that the hose is one meter longer than the diagonal of the room, and the tubes fit well to the holes.