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Well, you did already post something on hive: https://hive.blog/italian/@tormus1958/zipoli-4-versets-and-canzona-in-f, even though it was perhaps by accident. If know how to post on Steem, you know how to post on Hive. The difference is: the front-end, or web-address.
As with steem, Hive has several front ends you can use to log in. I'll name two:
https://hive.blog
https://peakd.com
If you're logged in on either front-ends, you're logged into Hive.

Logging in works the same as with Steem. And since Hive started as a fork of Steem, your keys and account-name on Hive are the same as on Steem. As with Steem there exist several browser plugins to assist with managing your keys securely. On Steem I use Steem Keychain, and on Hive it's counterpart is called Hive Keychain.

Should be a breeze. And if not, ask again and I'll try to help.