compiling docs

I have had a few problems with updating scrivener - I know I am a total moron with pc’s, but I do my best. I upgraded - lost the wrok, re-set, upgraded again - and I have managed to upgrade but it lost about 2 days worth of work - I can live with that - as it is probably my fault. Now I am not so sure, and am asking for help - but in english please - not pc language as I have no idea what you are talking about!
When I want to compile to a pdf doc, it says the docs are not where they should be and are somewhere on the hard drive ???

I am writing using scrivener, but when I want to compile what I have written it tells me not to be so silly as the files are elsewhere??? :open_mouth:

Can someone please help me put it all in the right place?