laila, you can mark something as correct or helpful when you have authored the question to the community. When you have a question you want to know an answer to, you can plug it into the search box to see if anyone else has posed a similar question. If not, then click "post" and follow the click through menus so that you can post a message to the entire forum. Note the little check box beneath your question, you have to check that you intend for your post to go out as a question.
Once you've posted your question, and have afforded fellow Insiders an opportunity to respond, then you get to assess who best answered your question It's at that point that you will see buttons appear in the answers to your posted question, and you will be able to press the button for the answer you feel is most "correct" and then two additional buttons for those that you deemed "helpful." I do hope you found this helpful
We look forward to hearing your first question soon, and many more discussions to follow!