How to make it remember certain information?

[Avastgard]

I would like to change some of the standard menu options to have the Utility:

1. compare the selected text with the content of certain text files and
2. generate a compared text on the GUI window that shows deleted words as strikethrough and included words as bold+italics.

2 Seems easy, as I would just have to write the instructions on the script.

1, however, eludes me. I guess I could paste the contents of the text file on the script itself as part of the prompt, but that doesn't sound like a good option, as the texts to be compared may change from time to time and it would be easier to just edit a text file instead of the script itself.

I tried adding a command to have GPT remember certain text, but it doesn't seem to work. I also read this on the API database https://platform.openai.com/docs/assistants/tools/file-search, but I'm not a programmer and it all went right over my head.

Is it possible to implement this on the Utility? Or is there another better way to do it?