Lost audio files


I have upgraded from Cubase 7 to 10.5 and I’m still getting used to the differences.
I have recorded a song with a choir and simply saved it as a project. When I reloaded the project the audio files are ‘not found’ but I don’t know how to go about finding them. The instrument files are on Halion Sonic and Sample Tank and they are fine.

Can anyone help please?