Good one @ScottsBuds ! 
For the purpose of this journal, I’ll assume they mean : How to create a journal
First you need to decide on a “Category” of journal and then a sub-category can then be assigned to further pinpoint what the journal will be about.
First start by clicking the “category” of any journal you happen to be on. That wil take you to the “new journal” section.
In this particular example, it takes me to the “Members Lounge” new journal section. Just click on the “Members Lounge” box and a drop down menu will appear with many different categories.
Pick your chosen category. That will bring you to that category “new journal” page.
Next you can assign (optional) a subcategory. That will just clarify what your journal is all about. Same thing as the first box, when you click it, a drop down menu will list the different subcategories available.
It’s easier to ignore the “tags” option for now. You’ll see it again when you start the first post of your new topic.
You’re now ready to create your topic. To do so, just click the “new topic” button at the top right of your window.
Now type an appropriate title in the relevant box, pick or create an optional tag, if you feel like it, by clicking the + arrow in the “tags” box.
Type in your text in the reply box, update pictures if you want.
Optional information: There’s 2 ways you can reply to a post/topic.
1:
If you want to respond/answer a reply you’ve just read, just click on the “reply” function at the bottom of the reply you wish to answer. This will reply to this user directly by tagging them in the reply (in the upper right corner of the reply window) and place the reply at the end of the journal, even if you’re replying to a 4 years old comment.
In the following example, you can see that @ScottsBuds replied to an earlier post from @Olaf.ILGM .
2:
Simply click on the big “reply” button at the end of the journal. This will place your comment at the bottom of the page and won’t be tagging anyone in particular.
And Voilà! You’ve created your first journal.