Hi,
1. "then" used to introduce the next item in a series of actions, events, instructions, etc.
e.g.
- First cook the onions, then add the mushroom. = First cook the onions, and after doing that add the mushroom.
2. also "then"used to show the logical result of a particular statement or situation
e.g.
- If you miss that train then you’ll have to get a taxi = If you miss that train, you'll have to get a taxi as a result of it.