Can't use the product after buying it.

Adobe says they are processing my order.  How long does that take?  In the menatime I can't use the product.  When I try to edit a PDF, I get a screen that says "Buy Now" or "Activate".  When I press "Activate", I get a message that says: "To activate confirm your Adobe ID.  After signing in you will need to close and launch Acrobat if you purchased an Acrobat DC subscription or entered a serial number."  I did that and get no response when I press the "sign in" button.  Please help.