How/what did you mean it?
How did you like the party?
Did you like the party?
"How" is used here in the same way as come/como (Sorry, Portuguese is beyond me. I hope you catch the meaning) ;)
The difference between "How did you like the party?" and "Did you like the party?" is the same as the difference between: Como te gusta la fiesta? and Te gusta la fiesta? (where gustar means "to like")
"What did you mean it" is wrong. It should be What did you mean? or What did you mean by it/that? What do you mean? = (Che) Cosa tu intende? How do you mean that = Como tu intende quella?
What do you mean by that? = Cosa tu intende con quella?
I hope you catch the drift.