too much
Google RST Manuals. I recently bought one for my Ithaca/SKB XL300 for about $7.00. It is a factory re-print and taught me everything I needed to know. They were very good to deal with.
You can go to just about any book store like barnes and noble and find plenty of books on gun prices. You just need to know what condition you gun is in and you can determine it from there.
Ther is a detent ring over the magazine tube where it enters the receiver that has to be rotated off of the pin it captures. Then you can remove the bolt carrier group block (a small square metal block ) then the bolt carrier group will slide out the end of the receiver (the bolt handle has to be pulled as well, just pull it out) assembly is reverse.