Complete beginner here. Never built or owned a gaming PC. Found this unit discarded and want to learn by restoring it. I have identified the following components from photos but need help confirming unknowns, identifying missing parts, and guidance on safe first power on. Photos available on request via DM.

Phanteks Enthoo Pro full tower case (white)
ASUS Z170-A motherboard
Cooler Master air CPU cooler (6 copper heat pipes visible)
ASUS Z170 Series GPU (graphics card, white shroud)
ASUS DVD/optical drive (visible in front bay)
RAM installed (4 slots, appears to have sticks in at least 2 slots, cannot confirm capacity or brand from photos)
M.2 SSD installed (labeled OS Drive on motherboard, likely has an operating system on it)
Front panel cables (partially connected)
Front USB 3.0 header cable (unplugged, blue cap, intact)
Cooler Master CPU cooler fan

Here is what I cannot confirm based on my limited knowledge.
CPU (hidden under cooler, cannot see without removing it)
PSU brand and wattage (saw EVGA badge on case exterior but cannot confirm from interior photos)
RAM capacity and speed
Exact GPU model number
Any additional storage drives

And here is what I can see that is fully missing.
One 5.25 inch bay cover or device (empty slot under optical drive)
GPU cannot confirm if fully seated or missing power connectors

Some questions I have.
1. Can you confirm what CPU this motherboard supports and how I identify mine without removing the cooler?
2. Is the ASUS Z170 Series GPU a real standalone card or the motherboard integrated graphics cover?
3. What do I need to safely power this on for the first time as a complete beginner?
4. Is this build worth restoring or parting out?

I’m willing to learn, and want to make this work if possible.

Thanks again!