I wish to know, how the LingQ flash cards system works, because I have many new words that are accumulating and I doesn’t see them anytime yet in the LingQs of the Day.
If someone could explain me, if this is normal or not, I appreciate.
The current system sends your words at fixed intervals, so if you don’t save LingQs for a while you won’t have as many words to review. We are, however, working on a system that will help make flashcard review on LingQ a bit more structured. Give it a little more time 
Maybe I wasn’t very clear with my doubt … I have many new LingQs saved ( 200+ ) ( the strongest yellow ), and many of them, was created a 2 or 3 weeks ago, and I didn’t see them anytime in a flash card, but I’m seeing many words that are with the status “Know”, but some of the firsts, which still with the “New” status, don’t are sending to me in flash cards, at the LingQs of the Day
Do you mean that you’re mainly being sent status 4 words in your LingQs of the Day emails?
At the moment there is no deck where words pile up, so if you create too many LingQs in one day and your LingQs of the Day is set at 25 or 50, for example, then you won’t see some of these cards.
You can, however, always go to the Vocabulary page and sort your LingQs by Status, Creation Date, Importance and more. You can also always go back to a lesson and click the “Cards” button in the My LingQs list at the right to review the LingQs from that lesson.