I just added a new list (Top 1000 words found in TV subtitles) of which I know many words of already. The list is divided into sections and I wonder why it is still adding the very first sections with with words that I all know already. Do I have to work through them again before the trickier sections with words that I don't know show up? I tried to manually work through the sections via the advanced study mode but it I'm running out of words often. What happens when I manually add words? Are they added to the advanced study mode and therefore to the list that I have selected or are they added in general? Thanks for your help!

It was adding from the very first sections because it needed to make sure you'd added all the parts for all of the words, and to associate those words also with that vocab list. This can take it a little while, since it has to scan through some words you already have before it can get to any new items that need to be added.

When you manually add words during the advanced study or normal study, it does associate those words with the list they're added from, and they are added to My Words.

You might want to just do Advanced Study on the list, but turn your Add Word Frequency to Fast instead of Slow.