If you are trying to add a card to the Zistle library and we don’t have that set or subset, you can easily add it.
On the collections tab, go to add cards to library on the lower left side of the navigation pane. Click ‘Add Cards to Library’
A pop-up window will appear.
On the right hand side of the window there are links to ‘add a set’ and ‘add a subset’. Please be sure that the set/subset that you are trying to add is in fact missing and not names slightly differently than you are expecting to avoid duplicate sets and subsets.
Click the appropriate link depending on what you are trying to add. Type the name of the subset and select save.
Once your set/subset is created, you can immediately add cards to that set and to your collection.