So you have to make sure the plants are at the stage of fertilization (making new baby plants). Then you have to make sure you have a male and female plant. You take the pollen from the anther of the male and place it on the stigma of the female flower, wait for the pollen to mature (like an egg growing). If the base of the female flower is swollen you have successfully cross bred 😀
You need to start off with 2 plants – most plants are hermaphrodites, which means they have male and female reproductive parts, so you don’t need to worry about getting a male and a female. (Some plants, like the Ginkgo tree, only have male or female parts but not many).
You need to take the pollen from one of the plants and put it onto the stigma of the other plant (take a look at this picture for a clearer idea of what that means: ).
This is exactly what a honey bee does. They pick up pollen from one flower and, as they rummage around for more pollen in another flower, some of it is rubbed off onto the stamen of the flower.
At this point, the ovule starts to swell as the plant makes seeds, which will grow into plants the next year. Congratulations! You’ve just had a baby!