You do not have to write the correct code. I think the instructions can be improved a little.
As you haven't learned about the _ as of Lesson 1 of Level 5 so you don't have to use it. This program should give an error because you will learn about using _ to handle response and error in the coming lessons.
Try this code:
package main
import (
"fmt"
"bufio"
"os"
)
func main() {
fmt.Println("Enter a number:")
reader := bufio.NewReader(os.Stdin)
userInput := reader.ReadString('\n')
fmt.Println(userInput)
}