Can you reveal hidden cards and play hidden cards and reveal hidden cards on your turn?
To answer your question, we need to distinguish between "revealing" a card and "playing" a hidden card, as they are governed by different rules.
1. Can you reveal hidden cards?
Generally, no. According to Rule 424.2, "Reveal" is a Limited Action, which means players can only perform it when explicitly instructed to do so by a game effect. You cannot voluntarily "reveal" a hidden card just to show your opponent what it is.
However, under Rule 128.4, as the controller of the hidden card, you are permitted to look at its face at any time because it is in a "Private" privacy zone for you. While you can show your private information to your opponent voluntarily (Rule 424.2.b), this does not count as the game action of "Revealing" and will not trigger any abilities that specifically trigger when a card is revealed.
2. Can you play hidden cards?
Only starting on the turn after you hide them. As clarified in the FAQ, you cannot play a hidden card during the same turn you hid it.
- Sequence: Hide on Turn A → Wait → Play from Hidden starting on Turn B (or any subsequent turn).
- When playing a card from hidden, it gains the Reaction keyword, allowing you to play it whenever a Reaction can be played (e.g., during your opponent's turn, or in response to a chain).
Summary for your turn
- Hiding: You can hide cards on your turn if you have the resources and open battlefields.
- Revealing: You cannot perform the "Reveal" game action unless a card effect tells you to. You may manually show your opponent the card, but this is not a game-action "Reveal" and does not trigger "When revealed" effects.
- Playing: You cannot play a card you hid on the same turn. You must wait until at least the next turn to play it from hidden.
This is my interpretation based on the Core Rules regarding Limited Actions and the specific FAQ entries for the Hidden keyword. No official FAQ exists for this specific combination of actions, but the rules regarding Limited Actions (424.2) and Hidden play restrictions (811.1) define these limitations.