Hello Fmywnd, yes it is an airplant called Tillandsia, there are many types and that one you got is a lovely one. You did just right, it likes to be mounted like an orchid, or you can use a glue to stick it to anything, or just rest it on marbles just like you did. But don't plant on soil. It may grow roots, but it is just for clinging on to something.
The plant makes a bloom, though really pretty when it makes it, it will mean it has reached the end of the line for the plant. But before it goes, after bloom dies, it will try to make new pups at the base, inside the lower leaves and it should continue on from there, while mommy plant slowly fades away.
Yes, you can dunk water the plant just like you did to water it, make sure to shake off excess water from the crown so it will not rot. Enjoy and happy growing!