I did years ago but I have completely forgotten how I did it. : o My comic's page has since been highly expanded by other people and (I see now--glad you brought this topic up!) moved, to here
And I could swear that when I originally did this, there was some kind of easy-to-follow guide... Hm. Which I cannot find. I guess what I would say then is to find a webcomics
entry that looks something like what you want to have for yours--you don't have to add any tropes to it to start with, your readers or other tropers can do that later--go to its edit page, copy the code, create your own page (I totally forget/don't know how to do this), and just paste in the code copied from the other page and then edit it to suit your own comic, removing any tropes attached to the code you copied. And then be sure to add it to the appropriate category of webcomics page list thingy (again copy and paste an existing entry and edit into your own, making sure to place it alphabetically, of course).
And finally, link it from your own site and tell your readers so you can get some folks over there to add tropes to it, etc.
That is totally not straightforward, sorry about that! Hopefully we will get someone here who actually speaks tvtrope. : o