Can someone please explain how they got the answer

35 of 60 Vigenere Cipher (1553) C-CiC-C3 K=[(ki,k-, P = P,P2P3 , k,n), (ki,k2, , k,n), ] Encryption: C Pi+k Decryption: P C k 3416cacrype the message Let us see how we can encrypt the message "She is listening" using the 6-character keyword "PASCAL". The initial key stream is (15, 0, 18, 2, 0, 11). The key stream is the repetition of this initial key stream (as many times as needed). b CD Plaintext:s he senn g P's values:18 07 04 08 18 1 08 18 19 04 13 08 13 06 Key stream:15 00 18 02 00 11 15 00 18 02 00 1115 00 C's values:07 07 22 10 18 22 23 18 11 613 19 02 06 Ciphertext: IH H w K s w|X S L G N TC G 3.35