How to keep car stero off when i turn off car.and comand whith ignition when ignition is on to turn radio and when ignition is off to turn off radio .

In your fuse panel there should b some empty fuse holders there should b one or more that are switched by your key a test lite or ohm meter will help you find the right one

There is a typically BLUE wire on the back of the stereo. Labeled “remote”. This gets 12V when you wire it to the ignition or accessory wire.

Simply removing key from ignition should turn radio off

On the wiring. You will see poss w wires with fuses some times only 1.
The red wire goes to a fused power that is constant ie right to battery or fuse power thats on when ign is not.
Then there is a black wire or maybe more then one those go to a good non painted ground.
The you have the yellow wire this also might have a fuse. This wire will go to a ign power on when key is on. It tells the deck to turn off and on..
The there is a blue wire this goes to the feed wire to your amp if you have one that wire tells the amp to turn on or off.
All grey. Purple. White and green are speaker wires. .
Its a good idea to not connect the ground speaker wires to the body ground. At all or you may not hear sound also if you do hear sound you might hear a low hum as you rev the engine this is feed back from the charging system. So be sure to connect the speakers for pos and neg. As needed there is no need to use the other speaker wires if you do not have 4 or more in the veh.
Hope this helps