Room service for breakfast

Sorry for the basic questions, but this will be our first cruise ever. We have the Plus package which includes room service. I see the typical stateroom breakfast is a continental breakfast. Can we order room service from the dining room so we can have a full breakfast in the mornings (at no additional cost to us)?

I know gratuities are technically included, but do you still tip in cash for room service? If so, how much is customary? Thanks!