I want to know about how to use this block on the subject of 7 x 7

ask [What's your name?] and wait //The user's answer...
(answer) //is stored in this "reporter" block.
when green flag clicked
say [Hello!] for (2) secs
ask [What's your name?] and wait
say (join [Welcome,] (answer)) for (4) secs //The "join" operator is useful for combining pieces of text.

The Scratch Wiki has pages for each block, including Ask () and Wait.

Welcome to Scratch, jojodojo2007!

When you trigger the ask block, it will pop up a text input on the screen. The person can type anything in, and the text will be stored in the reporter.