Future continuous is a tense that says an action of the future that is interrupt with another especific action in present, future, or past.
Structure: Subject + will be + verb + ing + complements

Exemples: 

• She will be buying a phone, but when she goes to the shop they didn’t have the tipe that she wants.
• You will be running the race, but you broke your arm last week.
• They will be studying, but the teacher says that there isn’t any exam.

We use future continuous to talk about an actions happening at specific time in the future in progres

Structure: will + be + ing + complements

Example:

• I will be cooking with my mom

We use the future continuous to indicate that an action is running in the future is interrupted by another specific action and to express actions in the process of being carried out or taking place at a particular time in the future.

It works with this structure subject + will be + verb + ing.

Examples:

1. I will be writing the letter tomorrow.
2. The baby will be playing the whole night.
3. I will be helping my mother to make breakfast.