The standard tip amounts will automatically be charged to your account on day 1 of your cruise. For the two of us on a 5-night cruise, this was $120.
If you do nothing, you'll receive 4 coupons in your stateroom near the end of your cruise that reflect that you've paid the standard tip amounts. There is one coupon each for your server, assistant server, stateroom host(ess), and head server.
If you contact Guest Services and indicate that you want to adjust your tips, they'll adjust the charge on your shipboard account and issue you four new coupons with the new tip amounts. If you want to pay tips in cash, you just contact them and have them remove the charge from your shipboard account.
The coupons come with fancy envelopes that are intended for you to use to present the tip coupon to the person receiving it. You can add cash to the envelopes as well.
Any tips you *charge* to your shipboard account will be forwarded to those they are intended for - even if you don't end up giving them the coupon/envelope. Cash has to be handed over personally.
I often adjust tips upward based on excellent service. Under the new system it is harder to do this. You need to go to GS, stand in line, get the form, fill it out, wait while they print you new coupons. There was no drop box option for this, and the line at GS on the last 2 nights of a cruise is often very long. The other option (which I did) was to take the standard tip coupon and add cash to it, as appropriate, in the envelope.