I registered an account today and made just one post. That means I am eligible for 14 activity addition every 14days. But due to I didn't make sufficient post, my activity will remain 1 (+13 unclaimed). Then, I wait again for another 14days and drop a post, I will have two activity (+13 and 13 unclaimed). So, after 1 month, if I begin to post frequently, I am entitled to 13+13 activity?
Exactly, you understand it correctly even though it is explained quite clearly in this quote.
★ You can technically get more than 14 activity in two weeks if you sign up between periods.
★ You only need to make at least one post in each activity period to be able to collect the activity at a later date.
Anyway I seem to agree with @ShowOff with his suggestion. The OP just needs to read more if he wants to know more about the forum and its rules. There are unofficial rules, how activity work, rankings, and also a merit system. I'm not forbidding users from creating a new thread for every issue they want to know an explanation for, but it's much better if they're willing to read a thread relevant to the issue.