Audio not working on my ubuntu 20.4 machine

-2021-10-17 13:23:51-- http://www.alsa-project.org/alsa-info.sh
Resolving www.alsa-project.org (www.alsa-project.org)... 207.180.221.201
Connecting to www.alsa-project.org (www.alsa-project.org)|207.180.221.201|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: https://www.alsa-project.org/alsa-info.sh [following]
--2021-10-17 13:23:53-- https://www.alsa-project.org/alsa-info.sh
Connecting to www.alsa-project.org (www.alsa-project.org)|207.180.221.201|:443... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: https://git.alsa-project.org/?p=alsa-utils.git;a=blob_plain;f=alsa-info/alsa-info.sh [following]
--2021-10-17 13:23:54-- https://git.alsa-project.org/?p=alsa-utils.git;a=blob_plain;f=alsa-info/alsa-info.sh
Resolving git.alsa-project.org (git.alsa-project.org)... 207.180.221.201
Connecting to git.alsa-project.org (git.alsa-project.org)|207.180.221.201|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/x-sh]
Saving to: ‘alsa-info.sh’

alsa-info.sh [ <=> ] 28.13K --.-KB/s in 0s

2021-10-17 13:23:56 (70.9 MB/s) - ‘alsa-info.sh’ saved [28807]

ALSA Information Script v 0.5.0
--------------------------------

This script visits the following commands/files to collect diagnostic
information about your ALSA installation and sound related hardware.

  dmesg
  lspci
  aplay
  amixer
  alsactl
  rpm, dpkg
  /proc/asound/
  /sys/class/sound/
  ~/.asoundrc (etc.)

See './alsa-info.sh --help' for command line options.

./alsa-info.sh: line 661: tree: command not found
Automatically upload ALSA information to www.alsa-project.org? [y/N] : y
Uploading information to www.alsa-project.org ... Done!

Your ALSA information is located at http://alsa-project.org/db/?f=cbf9e887cf0c746a45b9a7d8be782269ad8181bf
Please inform the person helping you.