20.04 sees all my external drives as read only

Hi my 20.04 has decided that all my external drives are read only which means I cant swap  files n folders.  How do I change this please....also my scrren goes off after 1 min I used to be able to extend the time via appearance in 16.04 but cant find how to do this on 20.04.  I am sure you guys have hidden it away somewhere....please help

cheers Diggsy