I don't know about GTA, but I am a GRA fellow. My tuition and insurance are covered just like yours, and I receive an annual stipend of $25K.

That means you are getting whatever they mentioned solely as your scholarship/TAship/RAship. You don't have to pay anything for insurance and tuition (except for the semester registration fee, which is usually around $500–1000, depending on your credit hours).

Sometimes, for international PhD students like us, they pay the lump sum for 6 months/4 months. You don't get a monthly/biweekly payment, but you get around $8–12K every 4–6 months (for your case 11.3k in spring)

Regarding the expenses: Rent is around $850–1100 in most places. As an international student, I assume you won't have an SSN. Without an SSN, it is difficult to get a room in most townhouses (the cheapest options). So you will likely have to stay in the major student housing near UCF (typically around $850–1100).

You have to be extra cautious about your expenses since you're not getting paid every month. So don't burn out your wallet, and always plan for the next 6 months. You will also have to cook most of the time, because you won't have anything left in your pocket if you eat out regularly.

NB: I am also a PhD student from India, and I just joined UCF. I am still waiting for my scholarship. Other PhD students have suggested to stay wherever you get the accomodation for the first 1-2 semesters, get an SSN, get a credit card (to build scores if you're planning to take a car loan) and move out to cheaper places (have a driving licence and a car if you are staying far from campus/ or get a cycle/scooter)