noob set up

I have tried looking ..but every post about initial set up immediately vanishes down a rabbit hole of RAID drives and third internal drives I'm just starting , and have taught myself basics with a single HDD PC (AMD FX 8core 4ghz / 64bit / 16gb RAM / 8gb GPU ) .. It's actually behaved quite well thus far ( Just doing HD, short , simple vids )
Now I've installed an WD 500gb SSD , installed OS and DV on to it......cleared the old spinny disc as drive D ..now I've no idea what to do. I've been told to put the files ( does this just mean the actual camera files ) or the project I'm working on onto the SSD ...So what do I use the D drive for ....in preferences there was simply

C:/user/desktop/videos ... desktop ??

I added 'D'

Is D where I want the cache to be? D I just change cache files location and Gallery stills location to 'D' in project settings??

A general accepted practice for Windows PC is to have the OS (Operating System) (Windows in this case) on one drive and everything else on other drive, or drives.

The system drive, traditionally labeled as drive ‘C’, contains the OS and all other user software (including DaVinci Resolve, in this case). It’s best to choose the fastest available drive for the system drive. SSD is a good choice, NVMe is better, if affordable and if the hardware supports it.

As for DaVinci Resolve, there are 3 additional things: the scratch disk, the media files and the renders. The scratch disk is where Resolve do all data manipulation while processing images during editing, color processing (grading) and compositing. It is the drive defined in DaVinci Resolve -> Preferences -> System -> Media Storage.
It’s best to put the scratch disk on another drive, separate from the system drive. This scratch disk would best be the fastest available drive, after the system drive. SSD is a good choice, NVMe is better, if affordable and if the hardware supports 2 NVMe’s.

If possible and if affordable, it’s better that the media files (those coming out from the camera) and the renders would be placed on another drive. This third drive don’t need to be very fast one, a spinning disk will do.

I agree with Josh.

My setup: C drive has operating system and davinci resolve on it. its a 240 gb SSD that cost 25 bucks.

My D drive is a 500GB SSD, cost 70 bucks. Thats what I use for scratch disk and media files.

I have an external HDD, 4 TB that cost 100 bucks. Thats where I back up everything and thats where raw materials live, such as unedited footage files etc.

Save money and invest in RAM storage. Fast RAM is what makes the process feel really fast. Look for speed, at least 3000-3200 Mhz, latency 15-16, size as much as you can afford. 32 gigs is great, 64 gigs is amazing.