Welcome aboard! Once you have a few more posts her, you can make a thread in the Member's Sale sub-forum where you list the Transformers you have on offer.
This place is a good start as it's the biggest Australian Transformers forum and it's easier to sell to people in the same country.
Until then, it would be a good idea to start sorting out what you have and taking pictures and listing their names if possible. Would be a good idea to try and take pictures of say a dozen-ish or so at a time so people can see them fairly clearly.