I've started a fresh account from zero where I post daily going over things like this. Tomorrow's post is exactly about what you're asking about. But let's see if I can summarize here while keeping it simple.

• To get SPT, you just have to post. You can buy it, but you'll earn it from posting too.
• Payouts are after 7 days. You can see your current holdings in your splintertalk wallet. You currently have 6.462922 SPT in your wallet (this is public)
• You can click the arrow button beside your SPT in your wallet to transfer, stake, or sell SPT. If it's in your wallet, it counts towards your SPS airdrop. 4 SPT = 1 SPS airdrop point. You don't need to do anything else.
• if you stake your SPT, you turn it into SPT power, giving you a more powerful vote when upvoting other people. This is a good thing to do, generally. Your staked SPT still counts towards SPS airdrops.

That's the quick and dirty. Post more, get more. Held and Staked both count towards SPS.