I want to use my amp on 5.1 system but i dont know how to connect , i connected the right/left input on the amp but i have only right/left output surrounds and subwofer does not have output signal then i used on stereo mode
That Aiwa is one very confusing piece of equipment. Your first photo is of the inputs, so we can ignore those. You have an Aux input, phono input, and the 5.1 input would be for something like a DVD or Blu-ray disc player that has a surround decoder built in and has 6 RCA outputs.
I also could not find the owners manual but only a service manual. The manual states that the speakers are 80W per channel (at 1% distortion), rear speakers 24W per channel and center speaker 24W. The subwoofer connection outputs 1V (it is a line-level signal, not powered).
Normally any powered output connections use speaker terminals like you have for your "Speaker" connections. What is confusing is that you have RCA connections for your rear and center channels. RCA would normally be for line level signals that you would connect to another amplifier. The manual however says 24W recommended into 8 ohms which implies that those RCA outputs are amplified and connect directly to speakers. So you can not use an extra amplifier for your surrounds or center.
The only connection that you can connect to an external amplifier is the subwoofer output. If you have two subwoofers it is ok to use a Y-splitter and connect the one subwoofer output to both subwoofers, or you can daisy chain from the first subwoofer to the second one.
I am not surprised that you get no subwoofer output in stereo mode. This is not a standard modern audio video receiver with computer processing. It is a basic mini-system and the subwoofer output only carries the signal from your 5.1 input. That means you have to have a DVD or Blu-ray player with 5.1 output including the subwoofer channel as the Aiwa subwoofer output only carries the subwoofer input signal.