Could anyone inform me about how to get in the union for acting and modeling, also how should I go about finding a agent for myself?

There is no effective union for modeling.

There are several actors' unions.  The two most relevant are SAG and AFTRA.  AFTRA is relatively easy to get into; being cast in anything and paying your initiation fee does it.  SAG is harder - you have to be cast in a principle role in three (or more) commercials or a lead in a movie, or equivalent work.  In both cases the initiation fee exceeds $1,500.

There's really no point in being in the union unless there are lots of union productions near you.  Most actors don't join until they have to.