The application of the pollen is very simple: if you have cut flowers and saved the pollen, with the help of a brush, a cotton ball, or even your fingers, sprinkle it on the feminized plant. Do this repeatedly for two or three days.
In this regard, it is important that the pollen not reach the buds of the lower parts of the plant, or its willowy parts. Nor is it advisable to pollinate complete buds, but rather the parts that retain the white, most receptive stigmas. It is also useful to prune all the flowers that have not been pollinated, as in this way the energy is concentrated on the buds that really matter to you, and the plant does not waste resources on parts you are not going to use. In this "artisanal" way, for low volumes, you will obtain several hundred seeds without any problem.