screen says welcome to Libra with a large five and drop a document here or pick and app from left side of the screen or create one . this does not help me to find my spreadsheets
If you go to File | open will that not allow you to open the document you require? I think you are opening the general Libreoffice package instead of the specific Calc package. If you find Calc in your launcher then you will go straight into a spreadsheet.
Hope this is of use!