Here's my TLDR after having serviced a shit load of those years ago, and getting the idea that you're looking to learn about hardware:
Take the passion and excitement you have for this learning adventure and apply it to an alternative project.
Now that's out of the way... I don't think you stand to learn anything about the hardware of the product past the "this part connects to this other part with a funny connector." Also, do not attempt to disassemble the display, the cabling sucks to deal with on those. If you're okay with this as an outcome, and are open to learning about troubleshooting... proceed!
There are lots of resources on troubleshooting "slowness" issues, so take a look on r/apple. Slowness typically has just a small handful of causes, and those causes can be filtered down based on when it occurs and if you have any other clues (such as a spinning pinwheel). Questions to ask: - Does the "slowness" issue happen all the time or just sometimes? - Does it occur with any application, or specific apps? - Does it occur immediately, or after a period of time?
The answers to these questions will lead you to either a software cause or a hardware cause. To better determine: - If it happens all the time, test the hardware, starting with the hard drive — Use the Disk Utility app to verify the drive. - If it happens with a specific app that isn't built in, check for updates or consult dr google about slowness with that app. If it happens with all applications, create another user account and see if it happens there; if yes, the issue is possibly related to the OS; if no, the issue only affects the one account — Use Activity Monitor to check for "All Processes" and look for large % CPU usage
Tools for going further: - Installation media for the operating system — For a computer of its age, that's going to be a CD, or a trip to a local Apple Store/authorized service provider - An external hard drive — You'll want to partition so you can boot from it as well as perform OS installations in the future as you mess with the computer - A Phillip's head screw driver, size PH 0 or PH 00 — Either will do, though I preferred PH 0
Potential Upgrades: - An inexpensive 2.5" SATA SSD — Look on new egg or amazon, don't spend more than $50 - RAM upgrade — I think that model officially supported 4gb, though will run 8. To be direct, 4gb (2 sticks of 2gb) will be more than enough for what you're looking at without spending much. Offhand, I think you need 204-pin DDR3 667 or 800mhz. This should be stupidly cheap, and you probably won't find anything at that low of a speed. A quick check of newegg has revealed some at 1066mhz for around $10 per module (again, you'll want two, and buying something that's faster than your computer can handle will result it in being used at the computer's speed... so don't "over buy") - Replacement Battery — Try to find an authentic Apple Battery. The knock off ones can be dangerous and typically don't last. Don't spend more than $50, and look on eBay?
It's late and I'm not sure where I this was going. Hope something in this wall of text was useful. Good luck!