Submitting a quote to the archive is fairly straightforward.
In the field labeled "Post #", enter the number corresponding to the post you would like to use, or quote from.
Click the + or - buttons in the reply section top bar to add or remove reply boxes.
Once you have enough reply boxes available, in each field labeled "Reply #" on the left side, type the number of the reply (or 0 for the original post) you would like to quote and press "Load". The reply will display in the large box on the right, however without quotes, images, videos, or links (to ease the archival process). Consecutive replies are preferred, but submitting out-of-order quotes for more hilarious results isn't against any rules.
Press the "Submit" button on the very bottom.
It's just that simple!