how do I try to find out what is going on with my car(my check engine light is on 1995 Toyota Celica

how do I try to find out what is going on with my car(my check engine light is on)I keep good maintanance on my car,

Asked by for the 1995 Toyota Celica
2 answers
scan the code and research possible causes
auto zone will scan codes then post. DO NOT BUY PARTS ON WHAT THEY SUGGEST