Update the tutorial existing information, one more time

Clarification and motivation

This issue is an updated version of #8 (closed), which in turn is a follow-up to #2 (closed), to refresh the existing info in the tutorial as they inevitably become outdated.

The story is the usual for these kinds of update: links need to be checked, mentions to the testnet have be updated and screenshots to be re-taken.

In particular this time around: the hangzhou2net testnet is in the tutorial, but jakartanet is its replacement for the protocol currently used in mainnet.

Note: this issue is only meant to improve the existing incorrect information, there is no need to extend this tutorial here.

Acceptance criteria

The outdated info mentioned above has been checked and updated.

If more was found to be broken or outdated it should be reported below and fixed as well.