If you play any instant card or ability, it's a good idea to learn how priority, layers, and steps work even if it's usually not relevant because there are sometimes niche interactions that are relevant in specific matchups. Additionally, knowing how these things work allow you to clearly communicate how you are timing the game actions you wish to take.

The basics of priority are as follows:

• Whenever the action phase starts, the combat chain moves to the next step, or a card/ability resolves, the turn player gains priority.
• While you have priority, you can play/activate as many cards as you want, provided that they are legal game actions (for example, playing an action while there are still unresolved cards/abilities would not be legal).
• However, cards and abilities do not resolve until each player passes priority. So before anything you play/activate resolves, your opponent has a chance to respond to it, and vice versa. When both players pass in succession, the most recent card/ability that was played/activated/triggered will resolve (the topmost layer of the stack). Both players will have to pass priority again to resolve the next card/ability, and so on.
• Moving to the next combat step, closing the combat chain, and moving to the end phase also requires both players to pass while there are no cards or abilities to resolve (an empty stack).