To install:

1. Open the battery cover on the bottom
2. Place the battery in the mouse and close the battery cover
3. Remove the USB-receiver from the bottom of the mouse
4. Place the USB-receiver in the computer
5. Switch the mouse on with the on/off button on the bottom
6. The computer will recognize the mouse and install the built-in driver, this might take a few moments.
7. The mouse is ready to use

This product doesn't need any drivers to function.
Just connect and the product should work.

You can switch the mouse off / on with the button on the bottom.

However, this mouse uses standby (sleep) mode to save battery power.
There is no need to switch it off.
When the mouse is not moving or there is no signal from the USB receiver, it will turn sleep-mode on, to save battery power.
When you use the mouse again, e.g. (depending on the type of mouse) by pressing a button, or by moving the mouse, it will switch on again.

For storage or travelling we would suggest to switch the mouse off and remove the batteries to avoid leaking.

Yes, it is possible to press multiple buttons simultaneously. 

Please note that this doesn't mean that all buttons can be pressed simultaneously, since this depends on the specific hardware of a mouse. Mice may have the hardware limitation that the thumb buttons can't be used together with left/right/mid click.

• Mouse arrow/cursor speed can be adjusted by clicking the DPI switch on the topside of the mouse.
• Alternatively, follow the steps in the mouse settings page

К сожалению задать кнопкам другую функцию не представляется возможным, так как мышь работает со стандартным драйвером системы. Специальной программки, которая позволила бы изменения функций кнопок, в комплекте не прилагается.  

Можно посмотреть в интернете, может быть можно скачать программку для программирования кнопок

Вот например с этого сайта http://www.highrez.co.uk/downloads/XMouseButtonControl.htm

Но заметьте, что это неофициальное решение и мы не можем дать гарантии, что данное ПО вообще будет работать с данной мышью.

It's not possible to provide a replacement receiver for this product.
This is due to the fact that during production the product and receiver receive a unique code, so the product can only communicate with the bundled original receiver.

• Try using the mouse on a different surface or use a mousepad.
• Clean the sensor on the bottom of the mouse with a dry cloth.

Unfortunately, we do not have service centers to repair products.
A defective product should be replaced by your point of purchase during the warranty period.

We offer a 'return to retailer' warranty on our products. In case of a defect, you can return the product to your retailer with failure description, proof of purchase and all accessories. During the warranty period you will receive a replacement product from the retailer if available. For full warranty conditions you can consult: https://www.trust.com/support/warranty

Although our keyboards and mice are designed for use with computers, they can be used on PS4. However please note, most PS4 games do not support a keyboard and mouse.

When using a (wired) keyboard or mouse with a PS4, make sure it connects well with the PS4. If the PS4 has a connection on the back, connect the keyboard/mouse to the USB-connection on the back of the PS4. Or alternatively use an extension cable or USB hub.

For more information, consult the PlayStation support website via https://support.playstation.com/s/article/Use-Keyboard-and-Mouse-with-PS4?language=en_US.

You can use our mice and keyboards on the Xbox One.

Please note that Xbox One supports the use of mouse and keyboard in some games and apps, but it doesn’t work for every game or app. The game or app publisher must enable this feature for their content.

For more information, consult the Xbox support website via https://support.xbox.com/help/Hardware-Network/accessories/mouse-keyboard.