vw beetle radio installation

Hi,i bought a 69 vw beetle and it didnt have any radio so i bought an original radio and i dont know how to install it.i know nothing about car so if anyone could please help me i would really appreciate it.the radio is the original one but i dont know how to do it.
Thanks
Lobo

Two wires are the speaker & the other two are power & ground. Ground should be brown, positive should be red or black.