What is your country and where did you get the amp ? With XLR and 1/4" inputs and 1/4" outputs, it is clearly a professional product. The amp has conflicting information. It is marked 220V 50Hz, but "USA" on the rear panel, whereas equipment for use in the US is 120V 60Hz. European equipment runs on 50Hz. It also seems like information near to where it says "USA" has been obliterated.

A user manual is not a must-have in order to use the amp. Its just that you will not know what the specs are. There is no fuse rating or maximum power consumption marked so that we can at least estimate what the output rating might be. Since it is bridgeable, it should drive 4 ohm loads in stereo mode with no problems, so you know that much. Input and output connections of any amp is straightforward. You don't need a manual for that.