Our Failed Attempt on Sagada Mountain Tea

We bought and brought home Sagada Mountain Tea leaves so that my mom and my sibling could taste them.  My little sister boiled them and it the color looked the same as the one we had in Sagada.  Upon tasting it tasted weird like sap.  We couldn't drink it.=(

So we asked our other friends who bought the leaves too.  They told us that we overcooked our tea leaves.  It was only supposed to be placed for 10 minutes once the water is already boiled.  Do you agree?  What's your method in making tea from actual leaves?