Theme Testing Site BackUp

Hey guys my name is sonuyos

and my site is http://www.sntdownloads.com

and as u can chek it that i hav edited my current theme a lot

so now i want make a demo site for editing my theme or addin somethin new…

so i hav created a sub domain and how to do it??

i mean how am i suppose to work and copy everythin??

and i hav tried copin SQL whole but it redirects sub domain to main domain :/