How to enable the sound on my HP470G8 laptop with Ubuntu 20.04.2 LTS running with WSL2 on windows 10 pro?

I have recently installed Ubuntu 20.04.2 LTS on my laptop HP470G8 within WSL2 on my Windows 10 pro. (NOTE: Is not dual boot). For that purpose, I downloaded Ubuntu 20.04 LTS from the Microsoft Store app after I set up WSL2 (Windows Subsystem for Linux). I suppose this version of Ubuntu is actually a server type (not desktop) because I found a sentence that best describes that difference on the internet.

While Ubuntu Desktop includes a graphical user interface, Ubuntu Server does not.

After Ubuntu installation, I got only Command-Line Interface what I expected because as I mentioned above Ubuntu 20.04.2 LTS is the server type of Ubuntu and does not include any GUI by default.

Example of my Command-Line Interface:

To get some GUI with my Ubuntu 20.04.2 LTS server I enter the following commands in the Ubuntu Command-Line interface:

sudo apt update && sudo apt upgrade
sudo apt-get purge xrdp
sudo apt install xrdp
sudo apt install xfce4
sudo apt install xfce4-goodies

sudo cp /etc/xrdp/xrdp.ini /etc/xrdp/xrdp.ini.bak
sudo sed -i 's/3389/3390/g' /etc/xrdp/xrdp.ini
sudo sed -i 's/max_bpp=32/#max_bpp=32\nmax_bpp=128/g' /etc/xrdp/xrdp.ini
sudo sed -i 's/xserverbpp=24/#xserverbpp=24\nxserverbpp=128/g' /etc/xrdp/xrdp.ini
echo xfce4-session > ~/.xsession

sudo nano /etc/xrdp/startwm.sh
!comment these lines to:
#test -x /etc/X11/Xsession && exec /etc/X11/Xsession
#exec /bin/sh /etc/X11/Xsession

!add these lines:
# xfce
startxfce4

In the end, I entered the final command to start the Remote Desktop Protocol server:

sudo /etc/init.d/xrdp start

After that command and "Starting Remote Desktop Protocol server" notification in the Ubuntu Command-Line interface I opened the Remote Desktop Services app from windows and set localhost:3390, user name and pressed connect button.

After successful login, I finally got GUI on Ubuntu:

My next step was to install firefox and I did it with this command inside Terminal Emulator:

sudo apt install firefox

After installation, I opened the youtube page in firefox and tried to listen to music but there was no sound.

QUESTIONS:

1. How to enable the sound at my Ubuntu 20.04.2 LTS?
2. Can I use any alternative which is better than the Windows Remote Desktop Services app?
3. Can I use any alternative to XRDP and XFCE4?
4. Is it a good idea to use Ubuntu 20.04.2 LTS to instal the Android Studio in it?