How do I logon to my home internet link?

Feel like an absolute newbie to Linux though in the past I have downloaded and installed various versions of Linux such as Ubuntu, Kubuntu, LinuxMini Knoppix and so on. I never felt like this that I cannot find a way to connect to my home modem to access the Internet. Right now I have Kubuntu 19.04 installed on one of my PC disks which I switch to try it out. However, just can't get to the first base i.e. connect the Firefox browser to the Internet. Kubuntu was so easy to start with ... maybe two years ago. So I thought I will try it again. No dice.

How do I do it? Where to begin ... which icon at the bottom right to click or from the Start pop-up menu at the bottom left? How/where do I search/select or type in the SSID and password? Simple questions right?

AJ