Method 1 (General):

By clicking on the "Start New Topic" button, you will see a pop-up window that let's you select where the new post should go (e.g. Ask Abby). 

You will then enter the editor, where you will need to:
1) Give the post a title 
2) Fill in the details
3) Click on the "Submit Topic" button at the bottom to submit the post. 

Method 2 (Specific Forum):

Our forum is divided into many parts (individual forums) with titles such as "Weekly Member News", "Introduce Yourself", "Ask Abby" etc. 

Click on a forum that interests you, then click on the "Start New Topic" button in that forum to enter the post editor. 

This second method allows you to skip the process of selecting a specific forum since you are already in the right place.