Does anyone have any tips for starting out as an archive researcher?

I have been set the task of sourcing the origins of a load of footage/stills (already found and set to be used in programme) and then clearing the rights. With only beginners experience I was wondering if anyone could offer any pointers for the most methodical way to go about this? How best to form a costing comparison doc? etc

I appreciate this is vague but any help would be greatly appreciated!

Thanks