Dear friend, I would like to include the documentation help of a toolbox with different packages
in Help->Documentation Center:> Installed add-ons

I created a folder with name Mytool in C:\Program Files\Wolfram Research\Mathematica\12.0\AddOns\Applications This folder includes the file: \Documentation\English\Guides\Mytoolhelp.nb

and I file paclet.m with this content:

Paclet[
    Name -> "Mytool",
    Version -> "1.0.0",
    MathematicaVersion -> "11+",
    Extensions -> 
        {
            {"Documentation", Language -> All, MainPage -> "Guide/Mytoolhelp.nb"}
        }
]

But the link to the help does´not appear in the Documentation Center -> Add-ons.