reg to auto

i got like 40 auto beans and 20 C99 F1's ...
my goal is to get the real deal C99 autoflowering whats the best way to make that`?

the F2's should be 25% AF right? so at F4/F5 they should be almost 100% AF

Lets say the genes for autoflowering is called A. Autlflowering is a recessive gene, so for the plant to autoflower it would have to be aa. Photoperiod strains (aka normal) don't carry this recessive gene, so they are AA. If you crossed an auto (aa) x regular (AA), the F1 generation would be 25% homozygous dominant (AA, no autoflower gene), 50% heterozygous (Aa, Non-autoflowering, but a carrier of the auto gene), and 25% Homozygous Recessive (truebreeding autoflower). This all sounds very confusing, but a Punnett Square is much easier to understand. By breeding a male and a female that autoflowered from the F1 generation, you would have 100% autoflowering by the F2.