Which configuration steps I should follow in order to make Ubuntu 18.04 seem more friendly to someone used to Windows 10?
For example: the extension "dash to panel", when the panel is at the bottom, provides a closer windows-like experience.
I'm not asking for icon themes in particular, nor templates, but functional configuration tips and ideas.
The absolutely best way is to stop using Windows as a crutch and dive into Ubuntu. The longer a person uses the crutch and keep trying to make Ubuntu windows would be the longer it'll take them to recognize the ease and facility of Ubuntu.
Ubuntu is friendly. It's substantially less of a curb of going from Windows XP or Windows 7 to Windows 10. When Microsoft made a radical change, moving to Windows 10, people kicked and screamed a little, but they moved on and adjusted.
The same would happen if when a user thanks of his goal, and just go for it in the environment the way it is.
Click on the applications menu and click on what you want to run, or type letters to bring up the app you want to use, and just use it.
Having used a computer can be springboard to the new environment... how to move the mouse, other elements of navigating. Other than that, look toward the task/object... don't look for Windows.
That is how to make Ubuntu seem more friendly to someone used to Windows 10.
You could add a secondary dock (Cairo-dock) from the repository. It makes Ubuntu resemble the Mac.
The Cairo-dock is a way to have a panel at the bottom as per the reference in your question.
It can be installed with this command:
$ sudo apt install cairo-dock
There are a number of other docks and tools you can install from the repository. If you install one you don't like, you can just as easily remove it with:
$ sudo apt remove cairo-dock.
To run a new installed application, such as Cairo-dock, search the applications menu.
A good way to do what you are looking for is to use Ubuntu in the form of Kubuntu or even better KDE Neon because of the KDE Plasma desktop.
Been already in a more familiar form for someone coming from Windows this can be a very important aspect. Also being so much customizable you can tweak a lot of option so to feel more comfortable as you try to get used to Ubuntu.
I personally believe that the most important aspect for people trying to get used to different operating systems is the desktop environment those operating systems are using. I think this is true especially for users that are not really serious about using programming or other specialized tools.
Generally speaking though, I don't think trying to get used to Ubuntu is going to be difficult especially if you really care to familiarize yourself with it and not simply to use it. Ubuntu is at its core easier than Windows in a lot of aspects. I personally find tweaking Windows and customize various settings is more difficult because their menus are a maze.
If you want to stick with Ubuntu though I believe that you don't really need to do much except for nostalgia reasons. As I said Ubuntu seems to me far simpler, especially for everyday usage. That is because:
The only thing that is going to help you immensely in the long run and is going to make the usage of Ubuntu far simpler is to just familiarize yourself with the terminal a bit. Nothing difficult at first but you have to learn how to install software for it with the command
sudo apt install PACKAGE-NAME
and uninstall with
sudo apt remove PACKAGE-NAME
More commands are going to come as you go along, you really don't need to focus on that and get nervous or anything because you can work without even using the terminal. It is just really helpful
Another nice advice would be to stick with as many programs you had in Windows as you can because you are going to feel more comfortable that way.
Concluding, I believe people that come from Ubuntu and have to work in Windows have to make them more user friendly, not the other way around.
