These are my pieces.
Rm 750x Corsair
Asus GeForce GTX 1650
x570 Aorus Elite
TridentZ DDR4 8gb x4
Ryzen 9 3950x
AMD Wraith cooler Fan
when connected it turns on for a split second and turns back off.
the Ram doesn’t show any lights and the motherboard lights do glow once in a while m.
Any suggestions ?
When you turn on power is the CPU Cooler fan running at 100%?
If it doesn't turn on it will only take a second for the processor to overheat and shutdown since that is a very high wattage processor.
If it is then try using just one stick of RAM and see if it boots up.
You didn't mention which Motherboard Trouble LED are lit.
Also disconnect everything from your motherboard except the GPU, PSU, CPU, Keyboard & Mouse, & one stick of RAM and see if it boots up at least into BIOS.
Is your Windows HDD/SSD partition MBR or GPT?
If your Windows Drive partition is MBR then BIOS needs to be in CSM Mode (legacy). Try doing a CMOS CLEAR to reset BIOS back to factory defaults.
Do you have all the Motherboard power cables connected? (6 or 8 Pin PWR AUX or something similar)?
Possibly you have something shorting out when you built your PC. If a Motherboard screw is shorting to ground as soon as you power up the PSU will shut down due to the short. You can try and see if you see any burnt or dark areas on the motherboard especially around the screws that holds the motherboard to the computer case.
If you remove everything from the motherboard except just the PSU and Motherboard and turn power on and see if the same problem occurs. If it does then you either have something shorting out or a defective PSU.
Is the Processor installed correctly without any bent or broken pins? You might want to double check that.