1) If you are definitely interested in participating, you can start eh applicatoin process here: http://wcupa.studioabroad.com/index.cfm?FuseAction=Programs.ViewProgram&Program_ID=10011. Just make sure you do not submit the make payment for the $100 application fee unitl I tell you.
2) Make sure you have a US Passport and that it is up to date. WCU rules require it to be valid for at least 6 months PAST our scheduled retune date. So, it must be valid up until about Jan 1 2019. If it is older and due to expire before that, go and get it renewed.
2) Here is a link to a useful travel checklist. http://www.flightnetwork.com/pages/travel-checklist-en/