Pick a theme, such as family, food or getting around, and learn just those words. The schedule is the same one the main deck uses, so a word you learn here is a word the main deck already knows.
Progress is kept in this browser, and accounts that would carry it between devices are not open yet.
How this fits with the main deck
One record for each word. A word has one stage, wherever you studied it. Learn 妈妈 here and the main deck will not teach it to you again as new.
Its own daily limit. Theme study brings in up to ten new words a day, across every theme you open that day. That is on top of the main deck’s fifteen. Reviews that are due are never limited.
The order. Words that are due come first. New words then arrive in the order the theme’s own page lists them, HSK 1 first.