As I could not manage to add the Lubuntu software center to the container

• put the container in the dust bin
• tried to create a new container: did not had the name I gave it (instead: ubuntu (focal fossa)
• tried to install the Lubuntu software center with
  Terminal:
  libertine-container-manager add-apt-repositery ppa:lubuntu-desktop/ppa && apt-get update && add-get update && apt-get install-package -p/--lubuntu-software-center

Acoording command from
https://lubuntu.me/lubuntu-software-center/
without sudo as the commands inside the container are root.

as neighter container could be created with my name
nor an app could be installed
I asked myself if it was wise to ignore the message on the start page of the Libertine Container manager:
Welcome to Libertine – the X11 Sanbox application Manager
You do not have Classic Application Support configured at this time.
Downloading and setting up the required envirement may take some time and network bandwidth.

Where can I configure the Classic Application Support?
Where can I download the required envirement?

@Keneda you are right, I tried it it both ways

Last try was with light always on, using the Manager Libertine Containers START button.
The container options I left unchanged.
Then a download started, might be the Classic Application Support ...
Now I could create a container.
Thanks for your help !

Hello
up to now I used a FP2 with UT 16.04.
On my new FP4 I am familiar with the standard apps of UT 20.04, how they are presented after installation.
THANKS TO ALL WHO MADE IT POSSIBLE !

Now I would like to install the first Desktop app Joplin on FP4.
Starting, I was not able to create a container.
Remark: You do not have Classic Application Support Configured ....
Is Libertine ready?
How can I create a container?