To install the very user-friendly web editor KompoZer within Ubuntu 16.04 LTS,
you may follow the following instructions:

Step 1: Open a Terminal window, then enter the following (pretty long) command there:
sudo apt-get install libatk1.0-0 libc6 libcairo2 libfontconfig1 libfreetype6 libgdk-pixbuf2.0-0 libglib2.0-0 libgtk2.0-0 libidl-2-0 libnspr4 libnss3 libpango1.0-0 libpng12-0 libstdc++6 libx11-6 libxft2 libxinerama1 libxrender1 libxt6 zlib1g
This will install the dependencies (if you are asked to enter the password at this stage, enter the Ubuntu user's password).

Step 2: For 32bit systems, enter the following four commands one by one:
(1) wget https://launchpad.net/ubuntu/+archive/primary/+files/kompozer-data_0.8%7Eb3.dfsg.1-0.1ubuntu2_all.deb
(2) wget https://launchpad.net/ubuntu/+archive/primary/+files/kompozer_0.8%7Eb3.dfsg.1-0.1ubuntu2_i386.deb
(3) sudo dpkg -i kompozer-data_0.8~b3.dfsg.1-0.1ubuntu2_all.deb
(4) sudo dpkg -i kompozer_0.8~b3.dfsg.1-0.1ubuntu2_i386.deb

For 64bit systems, enter the following four commands one by one:
(1) wget https://launchpad.net/ubuntu/+archive/primary/+files/kompozer-data_0.8%7Eb3.dfsg.1-0.1ubuntu2_all.deb
(2) wget https://launchpad.net/ubuntu/+archive/primary/+files/kompozer_0.8%7Eb3.dfsg.1-0.1ubuntu2_amd64.deb
(3) sudo dpkg -i kompozer-data_0.8~b3.dfsg.1-0.1ubuntu2_all.deb
(4) sudo dpkg -i kompozer_0.8~b3.dfsg.1-0.1ubuntu2_amd64.deb

At this stage, the KompoZer program gets properly installed!