How to Root HTC Desire 626s.

Link

you have to unlock boot loader in the first

Help me how to rooting for HTC desire 516

Hmm.. Also try Framaroot (link). Works on some device, hope it works in your phone too.

I tried it .. but didn't work

Have you tried using RootGenius (link)? Please note that there's a chance to fail and may cause phone malfunctions. Try it at your own risk.