Assuming this civilization has something similar in pattern recognition and language to humans they could likely learn plenty from any books that survive. Books are relatively delicate in that they are made of thin sheets of flammable biodegradable materials but we've discovered some very old books, papers, and similar materials that are still readable. This civilization would likely learn our languages much like we do, starting with illustrated books that have words that describe the items/nouns and actions/verbs being shown. As they learn words they can translate materials of increasing complexity over time.
The books would show what some real world items should look like and work like even if the items are damaged, decayed, rusted, and have parts missing. Damaged books would likewise have real world examples to build from to fill in blanks left from damaged pages or lost volumes of an album of books. Many photographs and motion picture films should survive to show realistic depictions of what things do and how they work.
The creatures that make up this civilization might have to be somewhat comparable in size and shape to humans, and have similar sensory perception, to make much of what we leave behind. If they view light/colors differently then ink on paper might be largely invisible to them, photographs might not match reality like we'd expect them to. If they have hands, or whatever, that are excessively smaller or larger than our own then it would be difficult to manipulate and explore the tools and utensils we leave behind.
I don't know how well digital records would survive if left without being maintained and protected. As it is now there's records lost because the machines built to store and replay them have been damaged and reverse engineering the systems has proven difficult without some frame of reference to work from.
Anything not "micro" or "nano" would likely be reverse engineered fairly quickly. We can teach a child to read and then from there a decade or two later they can practically teach themselves to take complex machines apart and put them back together, in the process learning how they work, then make repairs, adjustments, improvements, or some such shortly after. If the pieces are too small to see with the unaided eye, and manipulate with basic hand tools, then that's a specialty that could take far longer to master without guidance from someone already skilled in that field.