Some you just soak in water for a few (3 -5 or so) minutes and then drain 'em and use 'em. Others you soak for a few minutes, then toss in boiling water for another 3 minutes before you drain 'em and use 'em.
The packaging often says which one of the above is the case, but I don't think you can ruin them by soaking and then boiling for a few even if it's the "wrong" kind for that. (Lots of the packages are in Vietnamese, Korean, Chinese, Japanese, etc..., so I have no idea what they say! When in doubt I soak then boil.)