If I exceed Roth IRA income limit, and need 2 recharacterize all 2017 Roth contrib to IRA, do i include contribs & gains or just contribs? What is original contrib date?

My brokerage account company has me filling out a form for the recharacterization, and it says I'm supposed to figure out my gains and contributions on my own. I figured that out, but what do I put down for date of original contribution/conversion? I'm recharacterizing my entire 2017 Roth IRA contribution (plus whatever I put in for 2018 so far). Thanks!