The Rem. 740 is one of the most complicated rifles to disassemble unless you are very familiar with that action. Another rifle as complicated is the Win. Mod 100.
You may be able to find the proper procedure on the web. It would take many paragraphs to describe the right procedure.
Try the following link to assist you. Go very slow.
The Gun Digest "Firearms Assembly/Disassembly Part IV Centerfire Rifles" has the info you need. Lists for $19, you can sometimes get it on EBay for a lot less. If you don't want to buy it, private message me your postal address and I'll copy the 11 pages and send them to you.
I just ordered a copy of how to disassemble/assemble a mdl 742 from e bay; they had several assembly/disassembly remington mdls on there; I think I paid 6.50+ shipping. you might try e bay;