I don't know how to put things in the title description  If you want to add text to your post besides headline, you have to use the "Discuss" link below "Share A Link". If you mean text with a link in it for the comment section, the easiest is writing the text, highlighting it, then click the third button right above your post, which will open a box where you can insert link and click "create". Last, if you see others use "tricks" in their posts, you can click "source" below the post, then it is revealed how they do it. Example of a link with a picture.