How to build an addon settings panel?

[Zax]

I'm totally lost in the new way to display the settings of an addon.
I looked at the Vertical Layout example found at https://wowpedia.fandom.com/wiki/Pat....0/API_changes.
Sample code works and it is correclty displayed in my addon setttings panel but I would like to add some simple frames with texts (fontStrings), or simple buttons, to this panel.

Thank you for any help.

[Zax]

To be more accurate, I wonder how Combat section title is made in the following screen capture:

[Zax]

Using the "Canvas" form for a settings panel, I'm unable to deal with check button:

First, it looks weird:


Second, it doesn't work

local chkButton = CreateFrame("CheckButton", "ChkDarkui", parentFrame, "SettingsCheckBoxControlTemplate")
chkButton:SetPoint("LEFT", subFrame, "RIGHT", 40, 0)
chkButton.Text:SetText("checkbox label ***")
chkButton:SetScript("OnShow", function(self)
    print("show button") -- printed
    self:SetChecked(true) -- seems ignored !!!!!!!!!!!!!!!
end)
chkButton:SetScript("OnClick", function(self)
    print(self:GetChecked(), "check button click TEST")-- nothing happens !!!!!!!!!!!!!!!!!
end)