Almost everyone has memorized a vocabulary list once – and forgotten half of it by the next day. That is not your fault, it is the method's. Isolated words give the brain almost nothing to hold on to. Words in a sentence, by contrast, gain meaning, images and feeling.
Your memory works through connections. A single word is a hook without a wall. An example sentence provides the wall: it shows when the word is used, which other words it appears with, and what grammar it requires. That is exactly why you remember vocabulary from songs or films effortlessly – it hung on a scene. Context turns dry memorizing into real understanding.
Knowing a word and being able to use it are two different things. The English "run" can mean to sprint, to operate or to be valid – only the sentence decides. Learn just the translation and you still freeze in conversation. Example sentences show the typical patterns, so the words are available at the right moment. That is why in 1000 Words every word comes with an example sentence and is read aloud – you immediately hear how it sounds and fits.
Read or listen to the example sentence out loud, not just the bare word. After a short while, build your own sentence – the more personal, the better it sticks. And repeat those sentences at spaced intervals so they settle. Combined with the vocabulary trainer, which shows each word and its sentence again at the right time, you build vocabulary that is actually there in conversation – not just on the list.