My Lighsail Instance disck space is almost full and I need more space

My original disk space is 80 GB. I have created a snapshot backup and also went ahead and crteated a new instance of the same capacity from the snapshot. Now the challenge is :

1. How do I connect the newly created instance to my services ? Will the process disconnect my services and if yes how do I minimize the effects of service disruption ?
2. What happens to the snapshot ( backup) created after it is disconnected and my service is connected to the newly created instance ?
3. is the newly created instance empty in terms of diskspace . i mean is it exactly 80 GB SSH as at when I connect my service to it .
4. How long does it take the newly connect instance to be up and running ?

Expecting your response