To upload a file first you select the folder you wish to upload the item to then select the upload icon (arrow points to a cloud).
Once selected you will then be prompted to upload the file to the selected folder.
Once you have chosen the file you wish to upload, you will have a chance to view it then delete it if necessary before you upload it to the folder of your choosing.
Once you have uploaded the file you will then be able to view the file in the folder it has been uploaded to.
