I am currently in the process of submitting my very first product to the marketplace but I am somewhat confused by the instructions regarding the file structure. What I am submitting is really just a bunch of texture .png files, but the instructions seem to talk only about if you are selling something inside a project file. Do i need to create a project for my submission?
Yes you must create a project and set a folder structure up. Follow the instructions and everything will go smoothly! You also need to set up a test level that showcases the assets. You should create materials to showcase them.
You should probably set the materials up, not just submit the textures.
well… im submitting a color lookup table pack, which is a bunch of texture files that you just plug into any post process volume… but i guess i’ll put it into a project as you all say. 
They are correct. Everything must be set up in a UE4 project and ready to use. Happy to answer any other questions you’ve got!