In the event that you need to experiment, do not worry.
The worst that can happen with wrong connections is that the function does not operate.
PWR and RST leads are not polarity sensitive.
If you will build again in the future, buy a cheap front panel switch like this for testing.
https://www.ebay.com/p/4in1-PC-Powe...or-Computer/631889283?iid=142232821294&chn=ps
First get the power on leads correct.
Ignore the RST if you want, they are hardly ever needed.
The pwr on led and HDD activity leads are polarity sensitive.
If you have them reversed, the led lights simply do not function.
No harm if you get it wrong.