Open Drive
Navigate to the folder that you want to upload a file to
Press the + button - Choose upload
You now have the choice of uploading a photo/video or a file - click browse to add a document
Your most recent docs will now open in the files app - click browse to search for a doc
Choose a location - folder - file to upload
To delete a file that you have uploaded - Select the file - Press the ‘meatballs’ - Press remove - Remove in the dialogue box