By default, it is assumed you are sharing the files under the permissive MIT License which allows unlimited modification and commercial use of the file you have shared. If you prefer something like CC-BY (attribution required) or CC-BY-NC (attribution required, non-commercial use only) or other licenses, you should write the license type in your post.
For your own protection, it is recommended you put a license.txt file along with your file in a zip file, if there is IP that you would like to protect. If you’re just sharing freely with the community, then there is no need.
It is required by law that you are the original owner of the file(s) you will share or have permission from the owner to share it.
If you wish to retain fully copyright, you probably may not want to share the file - or at least not in source form.
This community is meant for sharing, so if the intent is to sell or commercialize any files, you should not host the file here but on your own servers or website and link to it.
You are more than welcome (within reason) to advertise any Gaea files, macros, presets, or other related products you’ve made.
We want you to be successful!