You mean how to grow your plants emersed?
Well, here's what I do with some of my swordplants. The same should be applicable with for example Cryptocorynes & other rosette plants, and mosses, too. But, you can't get every aquarium plant to grow emersed because some of them are truly aquatic (like Vallisneria, hornwort, etc.)
Stemplants: I would let them first grow out of your tank and then cut them and plant them in pots.
Also, try searching this forum with "emerse", "emerge", etc.