Question nothing but only a single led on my case turns on?

Jul 13, 2020
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this is my first time building a pc , I am using Ryzen 3 3200g, GIGABYTE GA-A320M-S2H,Thermaltake Versa H18 as a case and Thermaltake Smart 500W 80+ White as a powersupply . When i try to turn on the computer after putting everything in place only a single led in my case lights up and nothing else turn on not even the fans. and every parts are brand new.What should I do?