How to find my elo rating???


Your rating is determined from your results (win, draw, loss) against other rated opponents. That's it. So far as we know, this is the best way to measure chess skill.
Sometimes, a person's skills will be significantly better or than their rating. For example, if someone was rated 1500, and then didn't play or study chess for a year, they would not play as well as people who are rated around 1500. However, as a person plays more and more games, their rating will almost certainly be an accurate reflection of their skill level.