First go to the Content Browser, right click the Content folder, select Fix up Redirectors in Folder. (Some times I find there are still a few Redirectors lying around, do I need to restart my project after this and try again)
If you haven’t used any of the starter assets in your main project you can just delete the starter content folder
If you have used some assets delete the folder, but at the final prompt it should tell you what files are used in what assets/dependencies, and you can either replace, move or remove said assets out of your project and proceed with deletion.
If any starter assets were used you will need to run another Check for redirectors.
To keep things tidy and remove ghost files, navigate to you content folder in window explorer **C:\Users\Ethan\Documents\Unreal Projects**KiteDemo\Content, and delete any files not in use with the engine (engine dependant files are the Collections and Developers folders, but if they are deleted they will be regenerated upon startup).
If you arn’t comfortable with trying this out in-case you wreck some systems because you didn’t follow up on what was being deleted, clone your project so you have a back-up