The simple future tense is used to describe actions or events that will happen in the future. It often expresses intentions, predictions, promises, or spontaneous decisions.

Structure
There are two main ways to form the simple future tense in English:

1. With "will":
   - Subject + will + base form of the verb
   - Example: I will study tomorrow.

2. With "going to":
   - Subject + am/is/are + going to + base form of the verb
   - Example: She is going to travel next week.

Usage of simple future tense - 

1. For actions that will happen in the future
   - Example: He will arrive tomorrow.
   - (This simply states a fact about the future.)

2. To express intentions or plans (often using "going to")
   - Example: We are going to visit our grandparents this weekend.
   - (This shows a future plan or intention.)

3. For predictions about the future
   - Example: It will rain tomorrow.
   - (This is a prediction about what might happen.)

4. For promises, offers, and spontaneous decisions
   - Example: I will help you with your project.
   - (This is an offer or promise made at the moment of speaking.)

 Examples of simple future tense - 
- I will call you later.
- They are going to buy a new car.
- We will see a movie tonight.
- She is going to start a new job next month.

Time Expressions Often Used

Common time expressions with the simple future tense include:
- tomorrow: tomorrow morning, tomorrow night
- next + time period: next week, next year, next month
- in + duration: in two hours, in a few days
- soon

Key Points
- "Will" is generally used for promises, offers, decisions made at the moment, and predictions.
- "Going to" is used for planned actions or intentions and predictions based on present evidence.
  
The simple future tense is straightforward and versatile, used to express a range of actions or events that will take place in the future.