If you hit the faq in the light green bar upper right and scroll down you'll see how to do formatting for this brand of message board. Also, if you just hover over the grey box with the url link in the edit window you'll see an example of how to format.
For example, in yours above, if you want your words Weekly Weigh-In to be the link, you would write "Weekly Weigh In" and take the link
https://www.drmcdougall.com/forums/viewtopic.php?f=11&t=49400 for the September 2015 thread, and put it directly before the word "Weekly".
Highlight it AND the words and hit the URL button, so now it looks like this (I'm writing the word "close bracket" so it doesn't format correctly and you can see what I mean)
[urlCLOSE
BRACKEThttps://www.drmcdougall.com/foru ... 9400Weekly Weigh In[/url]
To make this clickable now, you have to erase that first close bracket and replace it with an equal sign and put that close bracket to the end of the link and before the words, right after those 2 zeroes and before the word "Weekly." Now it should look like this:
Weekly Weigh InGood luck!
(edited twice to correct atrocious spelling)