Oh! I finally can do it. For those that fine the exercise useless, let it be that you can do it first and you would see the use when the opportunity comes. Keep learning guys. signing.

Address: I can sign a message. Thanks to you OgNasty
Message: bc1q6z9sytz4lxcunk8m5nl2zejalnke4hy6d0jc7x
Signature: HyBgyT/rAWAG6naypvS24kDc41ope0vE0s4/+FjbRE3cVkgC0Ap5jIq9P8LrhsUJPc9GItySoTsBIZhSCrvbkpE=