sudo apt-get install valgrind check check-devel

Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package check-devel

I got scared by the last message (Unable to locate package...) because this
is my first Linux distro ever, and I don't want to mess with the OS. -Was that something to worry about?-

I know this is probably too much to ask, but I was wondering if you could create a guide
specifically for Pop! OS. There are a lot of new noobies who know nothing about Linux,
and the distro is growing like crazy in popularity. -ClamTK is available at the Pop! OS Shop,
but the last time it was updated was back in 2019-

Thank you very much for developing this software and for reading my email. :)