You can post a reply with the Rich text editor as follows:
Go to the topic you want to post a reply.
Click on the top or bottom of the topic.
Enter your message in the textbox. Use BBCodes to format texts, or insert images, videos and links.
Optionally, you can attach files to the topic by clicking Attach Files. The attachment size must be less than 20Mb.
Optionally, click Preview to view your reply before submitting it.