docs: Clarify environment variables (#1072)

### How do I share files with the host?

  Open 'File Explorer' and click on the 'Network' section, you will see a computer called `host.lan`. Double-click it and it will show a folder called `Data`, which can be bound to any folder on your host via the compose file:

  Open 'File Explorer' and click on the 'Network' section, you will see a computer called `host.lan`.

  Double-click it and it will show a folder called `Data`, which can be bound to any folder on your host via the compose file:

  ```yaml

  volumes:

### How do I install a custom image?

  In order to download an unsupported ISO image that is not selectable from the list above, specify the URL of that ISO in the `VERSION` environment variable, for example:

  In order to download an unsupported ISO image, specify its URL in the `VERSION` environment variable:

  ```yaml

  environment:

    - /home/user/example.iso:/custom.iso

  ```

  Replace the example path `/home/user/example.iso` with the filename of your desired ISO file, the value of `VERSION` will be ignored in this case.

  Replace the example path `/home/user/example.iso` with the filename of your desired ISO file. The value of `VERSION` will be ignored in this case.

### How do I run a script after installation?

### How do I configure the username and password?

  By default, a user called `Docker` is created during the installation, with an empty password.

  By default, a user called `Docker` (with an empty password) is created during installation.

  If you want to use different credentials, you can change them in your compose file:

  If you want to use different credentials, you can configure them (only BEFORE installation) in your compose file:

  ```yaml

  environment:

### How do I select the Windows language?

  By default, the English version of Windows will be downloaded. But you can add the `LANGUAGE` environment variable to your compose file, in order to specify an alternative language:

  By default, the English version of Windows will be downloaded.

  But before installation you can add the `LANGUAGE` environment variable to your compose file, in order to specify an alternative language:

  ```yaml

  environment:

### How do I select the keyboard layout?

  If you want to use a keyboard layout or locale that is not the default for your selected language, you can add the `KEYBOARD` and `REGION` variables with a culture code, like this:

  If you want to use a keyboard layout or locale that is not the default for your selected language, before installation you can add  `KEYBOARD` and `REGION` variables like this:

  ```yaml

  environment:

    KEYBOARD: "en-US"

  ```

> [!NOTE]  

>  Changing these values will have no effect after the installation has been performed already. Use the control panel inside Windows in that case.

>

### How do I connect using RDP?

  The web-viewer is mainly meant to be used during installation, as its picture quality is low, and it has no audio or clipboard for example.

  After configuring the container for [macvlan](#how-do-i-assign-an-individual-ip-address-to-the-container), it is possible for Windows to become part of your home network by requesting an IP from your router, just like a real PC.

  To enable this mode, add the following lines to your compose file:

  To enable this mode, in which the container and Windows will have separate IP addresses, add the following lines to your compose file:

  ```yaml

  environment:

    - 'c *:* rwm'

  ```

> [!NOTE]  

> In this mode, the container and Windows will each have their own separate IPs.

### How do I add multiple disks?

  To create additional disks, modify your compose file like this:

    - /dev/bus/usb

  ```

> [!IMPORTANT]

> If the device is a USB disk drive, please wait until after the installation is completed before connecting it. Otherwise the installation may fail, as the order of the disks can get rearranged.

  If the device is a USB disk drive, please wait until after the installation is fully completed before connecting it. Otherwise the installation may fail, as the order of the disks can get rearranged.

### How do I verify if my system supports KVM?