When you have club meetings, try to balance meeting time between addressing club business (special events, t-shirt orders, etc.), teaching kids information about Linux, and doing software lessons in which kids get to try doing things with Linux.
When conducting software lessons, it is a good idea to try to have enough computers for every kid, although having them partner with a friend can work if you don't have enough. Some things to try:
You can do a simple lesson in which students have to find and navigate to different files, folders, and apps within the default installation you set up for them. Can they find the Apps section? Can they do a search for a particular program? Can they open the file system and get to the music or downloads folder? Can they change to desktop wallpaper?
How about a troubleshooting lesson? Can kids check to see if they are connecting to the school’s wifi, and if they are not connecting, can they troubleshoot and fix it?
You can do a lesson about all the different ways to install software in Linux. Have them install a program using the Ubuntu Software Center. Have them download a .deb file from a website and install the program using Gdebi. Have them try using an AppImage. Have them install a program using a command in a terminal window. Have them try installing Flatpaks from Flathub. There are many ways to install new programs in Linux.
You can do a lesson built entirely around commands in a terminal window. For that purpose, we used this website: http://smashingtips.com/linux/cool-terminal-commands-for-linux. This gives kids a chance to install using the command line and see fun things happen as a result.
Distrohopping is the practice among Linux users of switching from one distro to another. Since you can run a Linux distro from a bootable flash drive without having to install it onto your hard drive. We built a whole lesson around that idea. Download the .iso files of several different distros and create a bunch of bootable flash drives for each. Then, have students try out a couple different ones during the lesson, comparing and contrasting what they tried. Here is a worksheet I wrote to accompany this lesson.
Depending on how much time you have, you can conduct a lesson in which kids are actually installing the operating system on computers. When we first started with our Linux club, we made it a point to upgrade the operating systems on the Linux computers in my room, giving kids the software and having them do it.
You can do a lesson in which kids are learning how to use specific apps, office stuff (Libreoffice), or getting experience in photo editing (GIMP), audio editing (Audacity), and video editing (Open Shot).
Not sure where to start? Fair enough. Luckily, you don't have to start from scratch if you don't want to. Our friends at the Open Source Initiative developed a Linux curriculum called FLOSS (Free/Libre Open Source Software) Desktops for Kids. The curriculum is broken down into 13 different lessons, each with its activity and assessment. It is a GREAT resource. I did not write this curriculum (credit for that has to go to Patrick Masson and a few other folks), but I endorse it wholeheartedly and it is used by both the Asian Penguins and the Penguin Corps. You can find more information about their program at this address: FLOSS Desktops for Kids.
There are lots of possibilities here, and you don’t have to be an expert on everything. One tip for conducting software lessons is to enlist the help of kids in your club who have shown an aptitude for different tasks. When we've done lessons on terminal commands or HTML, I've had some of the more experienced students lead the lesson, giving them a chance to demonstrate leadership.