need some help abut proteuss

i use protess for simulating the differnt circuits.
and use other softwares for pcb designing ,
i have just started to make pcbs on proteuss .can any one tell me how to
make single layer PCBs.
because when i autoroute it .it just give me the double layer PCB

you need to define in the properties in proteus..
go to System->set strategies
now select same layer for Pair 1 for Horizontal and vertical routing. you will get a single layer PCB design.