Well screen shots are always "too large" on this forum. So I will keep it on my desk…
Let's say that once "My Own Library" does not appear I can select "Show Style Library" at the left bottom of the empty window where the upper button "Add style to a new collection" is selected (impossible to select the button below this last one called "Add style to an existing collection"). Then I can select and open "My Own Library", where I discover my last defined and saved styles on what resembles a simple doc., what else after this ? No idea.
ALL THIS TO WISH YOU ALL A HAPPY AND BLESSED NEW YEAR FOR 2019

Yohanan