Problem is ----no input signal go sleep pls tell me what i do

That's very likely a dirty input connector.

Only one input signal per channel.

The Pre Out and PWR In for a method to insert an effects loop. The output signal from the Pre Out should be line level so you would not connect this to our microphone input on the PA, but preferably to a Line Level input otherwise you would overdrive the PA's input. When you connect the Pre Out, the 1/4" jack may interrupt the signal so you may lose output to the Champion's amplifier/speaker. If this happens, you need to have a return line with the same line level signal plugged into the AMP In to get your sound back on the amplifier itself.

Take the main outputs into a stereo input (or a pair of mono inputs) on the Peavey - without knowing which Peavey I cannot tell you further info re set-up but as you'll be sending line level signal you'll need to back off the gain on the channels you input to on the Peavey

Apart from the fact that there's NO information, Behringer+No input Signal=Low Voltage +15V -15V power supply issue.

Auxiliary output sockets (AUX 1-6) would usually be used for connecting to an FX unit input, with the signal levels sent to the FX unit governed by the AUX SEND pots from each input channel, setting the AUX MASTER at a level that will prevent peak signals from the various channels (sent to the FX unit) from clipping the AUX bus rails.
The output of your FX unit can be then be returned to stereo line input sockets (ST1-4).
For details see the GL2400 User Guide:
AUX OUT 1-6 (p.15),
AUX SENDS (p.17/18),
AUX MASTERS (p.19),
STEREO CHANNEL LINE IN (p.14).
If you require more precise EQ parameter control of FX return signals - and you have sufficient spare channels on the desk, connect to 2 x mono channel inputs:
one from left FX return, one from right FX return, with each of the console's input channels panned hard-left/hard-right (this assumes the FX unit has a stereo return).

First of all it is important that the amplifier must work to produce the output with an input signal. So disconnect and check with an audio test signal on the input line and at the coupling capacitor to the input. If this is fine then the fault is only the connection and it is possible that the input line has shorted and so the input is not acting. But if other inputs are working the connectors must be rewired and soldered once again without any bridging.

There are a number of configurations for a mixer like the 1832, the most common are PA system and Recording system. There are Main output jacks which carry the mix as summed in the main faders. These in a PA system would feed the pa amplifiers which drive the house speaker system for the audience. These connectors are XLR 3 pin type on the rear, intended for professional pa amplifiers which use balanced +4dbv line input level. Amplifier which have 3 pin XLR connectors for input signals can accept that high level signal. For home style HiFi amplifiers, the signal level is nominally -10DBv and balanced or unbalanced signal lines with 1/4in diameter phone plugs which are connected to the mixer by way of a second set of Main output connectors which are 1/4in phone jacks. Use whichever amplifier input level your amp has.
If you are not using it as a main PA house mixer, but using it for recording, the main output connectors go to a 2 channel recorder or computer sound card recorder. The power amp and your monitor speakers are connected to the connectors labeled "Control Room" (CTRL Rm). These output are useful for recording because the signal through the mixer can be monitored from several buses, Solo, main mix, selected by buttons provided. The buttons only affect the signal heard through the control room monitors, and not the main output which only sees the main mix so selecting "solo" does not interrupt the signal going to the recorder while the engineer in the control can be checking other signal paths through the board.

If you touch the area where the input and output level bars are (lower right of the screen) it will open a page called "Input Options".
Make sure the input and output gains are up about 75%. Usually the output gain is about 5-10% lower. If you're getting a button that says "No Input" where the input/output level bars should be on the lower right corner, it is telling you that your iPhone headphone/mic jack is not sensing the line from the Amplink. Leave everything connected, and exit the Ampkit program and then start it again. It should reopen with the level indicators showing. These connections are all finicky.

Usually the loop in is used with an EXTERNAL effects module where the audio signal is "looped" out through the external effect module and then back to the power amp to drive the speaker in the cabinet. The LOOP IN jack would receive signal from the EFFECTS module OUT jack.

The source to go TO the effects module INPUT may come from a jack such as preamp out, or sometimes the same loop jack if it usess the TRS (Tip-Ring-Sleeve) connection method.

If you do not have an external effects module, all this is a moot point in your case.