Second Query Formatting Help

Please explain the purpose of the formatting technique or the purpose of the function for each of the queries in the image below.

Worksheet Query Builder 13Query 5 14 SELECT INSTR('BROWNING, MARY','SUBSTR example" FROM DUAL; 15 16Query 6 17 SELECT SUBSTR ('BROWNING, MARY, INSTR ( BROWNING, MARY,+ "SUBSTR example" 18 FROM DUAL; 19 20Query 7 21 SELECT CONCAT 'SMITH',,' FROM DUAL 23Query 8 24 SELECT CONCAT (CONCAT ('SMITH,,', 'MARION') FROM DUAL; 25 26Query 9 27 SELECT LENGTH ('MARION SMITH') FROM DUAL: 28