Buy to open: Buying an option contract to establish a new position, becoming the buyer of the option. After becoming the buyer, you have two ways to close the position: one is selling to close, and the other is holding until expiration and deciding whether to exercise based on the situation.

Sell to open: Selling an option contract to establish a new position, becoming the seller of the option. After becoming the seller, you have two ways to close the position: one is buying to close, and the other is holding until expiration and deciding whether to exercise based on the situation.

The four steps of option investing.

1️⃣ is expectation, understanding your own view on the market—whether you expect a big rise or a big fall, or whether you don't expect a rise or don't expect a fall;

2️⃣ is strategy selection, in the options market, once you have an expectation, you can find a corresponding strategy, for example, expecting a big rise corresponds to buying a call option;

3️⃣ is opening a position;

4️⃣ is closing, for positions opened by buying, you can hold until expiration, or you can close the position by selling to close. — "3-Hour Quick Start to Options"