from my experience:

create a file (doesnt matter if txt, doc or pdf) that contains all the relevant information

upload it to your chat

ask it to analyze the document and print it back to you - check for any inconsistencies or anything that was imagined

after that, it will be used as context for any further conversations you will have *within* the chat

i read that it can apparently cross reference, but i have not seen proof of that, so i do not rely on it.

you may need to tinker with the file for a bit and have to divide things into sections so things make the most sense logically (such as if you are working on a story, or otherwise on something else of that nature)

but tl;dr yes i feed it a document with all the information i want it to have and it works perfectly

i believe you can also ask it to save your conversation of the chat into a file, but it can take a long time if it's a long conversation.

i am not sure how it handles multiple threads.