welcome Jellicoe
to answer your questions: worklists work on gentlemens agreement. it is not forbidden to draw a ship that is already drawn or on somebody's worklist, but avoiding drama we tend to keep to that. If you redraw a drawing already on our forums or main site, the best drawing gets placed on the main site, so both drawing quality and accuracy have to be good to do so
for uploading on the forums, you best use an external image host. quite a few of us use the public folder of dropbox, but that is not an option open to new dropbox users so other hosting sites are common as well.
for uploading on the main site (the completed drawings), the instructions should be all here:
viewtopic.php?f=11&t=5859