You should start with the simple bounty to understand how to do it. Twitter and twitter campaigns are easy
Launching a twitter isnt so simple and easy, you need to be updated with participants all of the time and check if they are really following the work.
The simplest would be telegram campaign. You just have to give them an instruction thats so very basic by directing them to a channel.
It's good to take part in a prize campaign but not for social media because most people complain that there are very few people sharing with very many social media campaigns, first do an analysis to not waste time without anything without getting anything.
I will only advise you to give all participants confidence, with a single point of error here will make your reputation worse in the eyes of the bounty hunter.