Hello I am new and I am a Protestant and I am here to learn about the Roman Catholic Church anyway my questions are these how do Catholics know that Saint Peter the Apostle was the first Pope ? Also is there any evidence that the Roman Catholic Church is the true Church from the Holy Bible ? Also my last question is how do Roman Catholics know that the Roman Catholic Church was and is the first Christian Church as opposed to the Eastern Orthodox Church like the Greek Orthodox Church thank you ?
Hi, well it might help to research the early Church Fathers and what they said about the Papacy… some of the quotes support the Catholic view, others seem to also support the Orthodox view, so it’s not completely clear cut. However, - the quotes that support the Catholic view are very clear. Here are some of them

(it would be helpful to maybe look at them in context as well)
“He passed over his fall, and appointed him first of the Apostles; wherefore He said: ‘Simon, Simon,’ etc. (in Ps. cxxix. 2). God allowed him to fall, because He meant to make him ruler over the whole world… that, remembering his own fall, he might forgive those who should slip in the future.” Saint John Chrysostom, Patriarch of Constantinople (c. 387), Father and Doctor of the Church (Chrys, Hom. quod frequenter conveniendum sit 5, cf. Hom 73 in Joan 5).
“Peter, set above the Apostles.” Saint Peter, Bishop of Alexandria (306-311)(Peter of Alexandria, Canon. ix, Galland, iv. p. 98)
“Moses was succeeded by Peter, who had committed to his hands the new Church of Christ, and the true priesthood.” Saint Macarius of Egypt (371) (Macarius, Hom. xxvi. n. 23, p. 101)
"(Peter), the foundation of the Church, the Coryphaeus of the choir of the Apostles, the vehement lover of Christ …he who ran throughout the whole world, who fished the whole world; this holy Coryphaeus of the blessed choir; the ardent disciple, who was entrusted with the keys of heaven, who received the spiritual revelation. Peter, the mouth of all Apostles, the head of that company, the ruler of the whole world. Saint John Chrysostom, Patriarch of Constantinople (c. 387), Father and Doctor of the Church (De Eleemos, iii. 4; Hom. de decem mille tal. 3)
“And why, then, passing by the others, does He converse with Peter on these things? (John 21:15). He was the chosen one of the Apostles, and the mouth of the disciples, and the leader of the choir. On this account, Paul also went up on a time to see him rather than the others (Galatians 1:18). And withal, to show him that he must thenceforward have confidence, as the denial was done away with, He puts into his hands the presidency over the brethren. And He brings not forward the denial, nor reproaches him with what had past, but says, 'If you love me, preside over the brethren …and the third time He gives him the same injunction, showing what a price He sets the presidency over His own sheep. And if one should say, ‘How then did James receive the throne of Jerusalem?,’ this I would answer that He appointed this man (Peter) teacher, not of that throne, but of the whole world.” Saint John Chrysostom, Patriarch of Constantinople (c. 387), Father and Doctor of the Church (Chrysostom, In Joan. Hom. 1xxxviii. n. 1, tom. viii)
“Yielding honor to the Apostolic See and to Your Holiness, and honoring your Holiness, as one ought to honor a father, we have hastened to subject all the priests of the whole Eastern district, and to unite them to the See of your Holiness, for we do not allow of any point, however manifest and indisputable it be, which relates to the state of the Churches, not being brought to the cognizance of your Holiness, since you are the Head of all the holy Churches.” Emperor Justinian (520-533), writing to the Pope (Justinian Epist. ad. Pap. Joan. ii. Cod. Justin. lib. I. tit. 1).
“They (the Apostles) strove to learn through one, that preeminent one, Peter.”
-Saint Cyril of Alexandria (c. 424) (Cyril, Ib. 1. ix. p. 736).
“Let your Apostleship show that you have worthily succeeded to the Apostle Peter, since the Lord will work through you, as Supreme Pastor, the salvation of all.” Emperor Justinian (520-533) (Coll. Avell. Ep. 196, July 9th, 520, Justinian to Pope Hormisdas).
“I therefore beseech your holiness to persuade the most holy and blessed bishop (Pope Leo) to use his Apostolic power, and to order me to hasten to your Council. For that most holy throne (Rome) has the sovereignty over the churches throughout the universe on many grounds.”
-Theodoret, Bishop of Cyrus in Syria (450) (Theodoret, Tom. iv. Epist. cxvi. Renato, p. 1197).