Welcome aboard, mate. You've bought a delegation of heaps more than you'll need.
I went to drop a delegation of 50 SP, then realised you certainly won't need it, at least for the next 90 days. As tenkminnows mentioned; use that SP to upvote carefully for curation rewards, and power up what you get back. You won't need much SP to play, unless you're running a bot.
See you out there, mate :)