Understanding Transformers Self attention calculation

Regarding this link: https://www.analyticsvidhya.com/blog/2019/06/understanding-transformers-nlp-state-of-the-art-models/?utm_source=blog&utm_medium=demystifying-bert-groundbreaking-nlp-framework#comment-160771

What is the value of Key, Value in the self attention calculation of Transformer model. ?
Query vector is embedding vector for the word that is queried, is that right?
Is attention calculated in RNN is different from self attention in Transformer?

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