With an electrical shock the first thing you should do is to

To separate the person from the source of electricity as quickly as possible. Simple

Explanation:

Separate the person from the electricity source: If they have got stuck first thing you need to do is switch off the source of electricity or it’s even better to remove the fuse. Use a non-conductor to break the connection of current like wood, plastic. Make sure that you are not standing on anything that is wet.