It can take time for your file to be uploaded to Moodle and for it to be processed by Turnitin. This can be anywhere from a couple of minutes to up to 30 minutes per file, depending on the size and format of your file and your connection speed. Ensure you leave yourself adequate time to successfully submit your assignment, especially if you are submitting multiple large files.
If you have uploaded the wrong file in error you may be able to upload a new assignment file prior to the assignment deadline. This process will overwrite your original submission. The ability to resubmit your assignment depends on how the assignment submission has been set up. If you are unable to see a link called Submit Paper you will not be able to resubmit your assignment and should contact your course officer.