How do you get the other forms of wormadam

To get all the forms of wormadam you need to battle burmy in different places and get it to
level 20.
To get sandy cloak wormadam you have to get burmy to level 20 on a beach or cave.
For plant cloak wormadan you need to get burmy to level 20 in grass.
For trash cloak wormadam you need to get burmy to level 20 in a building.
Once you do this burmy will evolve into wormadam and be one of the 3 different forms
depending on where burmy evolved.