if you are in the portal, click on the "INDEX" found on the upper buttons
next, click on the category where our post belongs to (example: you want to post a topic for the sophomores, click on the sophomores category),
next choose a forum where it belongs to (example the announcements forum) ,
then click on the "NEW TOPIC" found on the upper left corner.
Next type in the title of your post on the box for the subject,
and the content on your post on the bigger box in the center,
click send right after.