Speaker box project. Need a little help

[Camg]

Hi all,
I'm new to this forum and new to this hobby. It's my first project and I've done a ton of studying about electronics in the past few months, but I haven't even scratched the surface haha. So if someone could help me it would be much appreciated.

I'm building a portable speaker box.
It has a tpa3116 (sanwu blue) 50w x2
A 12v psu
And a 12ah 12v battery.

I just need to find a way to have one switch to switch it from just using the battery, just using psu, just using battery charger or both battery charger and psu together.

I've tried to make a schematic of what might work but yeah please help out where you can

(The yellow box is one switch)

 

[Camg]

Anyone?
Im really struggling to find a switch that will work

 

[duke37]

You have three switches there, which do you mean?

Please redraw your schematic with a common rail along the bottom and the mains and low voltages separate.
I do not know what the bolt in the centre is.

 

[Camg]

Ah right. Here it is. The black box will be a main switch. Only one can be on at a time.
Will this work? Or is there a better way because I'm struggling to find a switch to suit.