HELP!!! Why won't my GPU work

I recently got the funds to buy and build my pc. Now i don't know anything about building so my mate came to help set it up and the graphics card doesn't give me any image it worked for a wee bit but after turning it off and o it didn't work. And directly in the motherboard doesn't work either. And everything else works fine, the GPU does get power.

This is in my pc: The case is: HYTE Y70. AMD RYZEN 7 7800x3d Processor, NVIDIA GeForce RTX 5070 graphics card, ASUS ROG STRIX B650E-F GAMING WIFI motherboard, 16GB DDR5 ram, 850 watt modulair gold powersupply, 2 TB SSD M.2