How do I install software center on Ubuntu 18.04

I can't launch the Software & Updates center in Bionic Beaver. No video application will open. I tried to install the software center manually and got the following output:

neil@neil-ThinkPad-T420:~$ sudo apt-get install software-center
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package software-center is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'software-center' has no installation candidate

I'm not a technical adept and can barely follow simple terminal instructions. I need help.

software-center has been replaced with gnome-software. So just type in a terminal

sudo apt install gnome-software

as quality of packages in Ubuntu is going down the drain, Synaptic Package Manager is a decent replacement to Ubuntu Software Center, and is much better (far less buggy) than Gnome Software.

you can install it with:

sudo apt install synaptic

If you want to get Software & Updates - it is located in software-properties-gtk package.

You can install it with:

sudo apt update
sudo apt install software-properties-gtk