OP, I see that this is your first post on the forum, and that you became a member only a few days ago.
So instead of introducing yourself to the forum community, and sharing your interests, your first question is about merit.
By using the simple search option, you would find hundreds of such questions on this forum and immediately see the answer.
The answer is very simple. If you want to get something, you have to give something first, and what that depends solely on you, your knowledge, experience, interests etc.
There is nothing wrong in asking how to get merits because merits is a very big part of this forum. It is something we cannot shy away from. Without merits ranks would be stocked and stagnant and the forum may become boring.
Everyone in the forum needs merit and it is good to know how to earn it legitimately.
Op, you get merits when you make quality posts and quality posts are the posts that provide information and solve people's problem.