sudo apt install plank

 $ sudo apt install plank
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following package was automatically installed and is no longer required:
  libfprint-2-tod1
Use 'sudo apt autoremove' to remove it.
The following additional packages will be installed:
  bamfdaemon libbamf3-2 libplank-common libplank1
Suggested packages:
  libplank-doc
The following NEW packages will be installed:
  bamfdaemon libbamf3-2 libplank-common libplank1 plank
0 upgraded, 5 newly installed, 0 to remove and 0 not upgraded.
Need to get 538 kB of archives.
After this operation, 2.345 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://id.archive.ubuntu.com/ubuntu focal/universe amd64 libbamf3-2 amd64 0.5.3+18.04.20180207.2-0ubuntu2 [53,2 kB]
Get:2 http://id.archive.ubuntu.com/ubuntu focal/universe amd64 bamfdaemon amd64 0.5.3+18.04.20180207.2-0ubuntu2 [88,2 kB]
Get:3 http://id.archive.ubuntu.com/ubuntu focal/universe amd64 libplank-common all 0.11.89-1 [55,3 kB]
Get:4 http://id.archive.ubuntu.com/ubuntu focal/universe amd64 libplank1 amd64 0.11.89-1 [247 kB]
Get:5 http://id.archive.ubuntu.com/ubuntu focal/universe amd64 plank amd64 0.11.89-1 [94,7 kB]
Fetched 538 kB in 4s (136 kB/s)
Selecting previously unselected package libbamf3-2:amd64.
(Reading database ... 183207 files and directories currently installed.)
Preparing to unpack .../libbamf3-2_0.5.3+18.04.20180207.2-0ubuntu2_amd64.deb ...
Unpacking libbamf3-2:amd64 (0.5.3+18.04.20180207.2-0ubuntu2) ...
Selecting previously unselected package bamfdaemon.
Preparing to unpack .../bamfdaemon_0.5.3+18.04.20180207.2-0ubuntu2_amd64.deb ...
Unpacking bamfdaemon (0.5.3+18.04.20180207.2-0ubuntu2) ...
Selecting previously unselected package libplank-common.
Preparing to unpack .../libplank-common_0.11.89-1_all.deb ...
Unpacking libplank-common (0.11.89-1) ...
Selecting previously unselected package libplank1:amd64.
Preparing to unpack .../libplank1_0.11.89-1_amd64.deb ...
Unpacking libplank1:amd64 (0.11.89-1) ...
Selecting previously unselected package plank.
Preparing to unpack .../plank_0.11.89-1_amd64.deb ...
Unpacking plank (0.11.89-1) ...
Setting up libbamf3-2:amd64 (0.5.3+18.04.20180207.2-0ubuntu2) ...
Setting up libplank-common (0.11.89-1) ...
Setting up bamfdaemon (0.5.3+18.04.20180207.2-0ubuntu2) ...
Rebuilding /usr/share/applications/bamf-2.index...
Processing triggers for hicolor-icon-theme (0.17-2) ...
Processing triggers for gnome-menus (3.36.0-1ubuntu1) ...
Processing triggers for libglib2.0-0:amd64 (2.64.3-1~ubuntu20.04.1) ...
Processing triggers for libc-bin (2.31-0ubuntu9.1) ...
Setting up libplank1:amd64 (0.11.89-1) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for desktop-file-utils (0.24-1ubuntu3) ...
Processing triggers for mime-support (3.64ubuntu1) ...
Setting up plank (0.11.89-1) ...
Processing triggers for libc-bin (2.31-0ubuntu9.1) ...