How do you keep individual chapter heading and add in an additional title

Hi, Thanks in advance to anyone who can help with this. I want to add an additional title to my chapter numbering: ie. Chapter one - January on one line. I’ll take it on two lines at a push!
So looking to achieve either:
Chapter one - January OR
Chapter one
January
Despite reading here on the forum and other web pages, I can’t work out how to do this.
At the moment My manuscript within the binder is arranged with a blue folder and under this sits my chapters for that month. Then a new folder titled February and so on. Each scene sits under a folder (say February) I’ve labelled ‘chapter.’
But when I enter compile, I get a very different layout than that described in the support pages. I don’t get a formatting option.
Can anyone help me out, please? Thanks so much:-)

Click compile. In the left-most pane you will find the compile format you are using selected. Double-click on it. If it is a Scrivener standard format you are using—which I suppose—you will get prompted to Duplicate & Edit as the standard formats are kept unchanged. Do so and save it under a name of your choice.

Then you will be in the settings of your compile format. Again in the left pane you will find what you are looking for—Section Layouts. Which ones you got in the upper right pane depends on your template. Each on of them has settings to automatically create the desired content.

For the section applied to your folders the box Title must be ticked. Text is optional.

In the Binder your folders should be named after the months. Then you could add under Title Options/Title Prefix both text like “Chapter_” and the placeholder <$t> and “” (please note that I just used underlines instead of spaces to make them visible!). The placeholder <$t> creates “One”, “Two”, “Three”, &c.

That should work. You could add a Return in between if you like. Play around with it to get exactly what you want. Under Help you will find a list of all placeholders, the section Auto-numbering is the one you will look for. This list is a bit overwhelming at first but once you got into it you will find how much flexibility they allow.

Looking them up in the manual will be very helpful too.

PS: If my explanations were not good or if you are more a visual type of person just tell us which Compile format you are using and somebody here could provide you with screenshots.

My goodness, thanks so much for your prompt response. Quite right, I didn’t think to double-click on the selected format, I now I see that formatting window. Easy when you know how - much appreciated. I’ll give it a go, your instructions seem very clear. Whilst I am it, I’ve heard I can check spelling and grammar but if I go to EDIT> Spelling & Grammar, I get a drop-down of four items:
Show spelling & grammar
Check document now (greyed out which is the one I was hoping to use)
Check spelling while typing
Check spelling with grammar

Why is that option greyed out and how can I select it? Thank so much Suavito:-)

So I tried that, but think I’m confused because now my manuscript is just blank pages marked with numbered chapters but the body text is gone. Am I able to share screenshots with you? Or are you able to screenshot the process and share it with me? Still, no luck getting the spell-check to check the entire document now, and the page is removed under support. Sorry to be a burden!

If you get blank title pages you probably chose Title page without text. There are several different main alternatives which you can modify once you have connected them to the correct parts of your Binder structure.
I think there is a brief explanation of the Compile process in the interactive tutorial, found under help.

Here are a couple of worked out examples — very different products from the same content.

Chapter Headings

a synopsis/epigraph report