You have to find a digi - egg in a chest. You then have to go to your home and go to the digi - lab and click on special digivolve. You then click on the digimon you want to armor digivolve. There...
First of all you will need the right digi egg. then you will need to train your digimon to the right level/stats. After that you will need to go to your home/farm and go to the digi lab, select...
You can find armor digieggs in the wild then you go to the digilab click special digivolve click the digimon you want to armor digivolve and your done. PS:your digimon has to be at a surtane level