Let me help you understand the chapter select system - it's actually pretty clever once you know how it works. First, make sure you've loaded your most current save file (this keeps all your hard-earned progress intact), and create a backup save just to be safe. You'll find the chapter select option waiting in the story section of the main menu after finishing the campaign.

Here's something interesting - the game tracks collectibles per chapter, so you'll need to be methodical about this. When you're collecting those missed items, always double-check they appear in the chapter summary before moving on (this is because some players have reported items not registering if they exit too quickly).

The reason we need to be careful with saves is that chapter select essentially resets that specific chapter's collectible status to how it was in your original playthrough. So when you're grabbing those missed collectibles, you'll want to collect them in order as you go through - jumping around might cause tracking issues. This system was actually designed specifically for trophy hunters, making it easier to target specific chapters rather than doing full replays (which would take considerably more time).

Quick side note - if you're planning a thorough collectible hunt, maybe keep a simple checklist handy. It helps avoid that frustrating moment when you realize you missed something again!