"How can I perform doping of silicon manually? "

What dopant do you want to apply? What is the nature of the silicon
substrate? In general, you need a way to apply a closely controlled
concentration of the dopant onto the surface. Arsnic and phosphorus
can be applied as a liquid. Boron is typically applied in a vacuum
either through ion implantation or LPCVD. There are many texts that
explain the theory.