I challenged myself to help you get started as quick as I could.
Journalling with cartoons is about drawing for yourself. To entertain yourself. To tap into something that maybe you want to say, or maybe just to get back into drawing for the fun of it!
My personal method is to include a lot of improvisation, I don't plan a cartoon I see what pops up - and this video shows that perfectly.
We can talk about what to do next with your characters later, but for now enjoy their little faces - which one do you like? What do you think they are saying?