Yes as long as they have the new testament they can start just as the first century Christians did with the word of God only. Same as us today, lets go back to the word of God and start there. New Testament Christianity from the first century in the 21st century. Nothing added and nothing taken away. Make sure the bible is a good translation. The words that were given in the beginning have the same meaning as they did then, now. False teachers must change the meanings of the words to teach damnable doctrines. We have all the meanings of the words from the bible in writings from that period in museums and higher places of learning.
1Co 1:10 Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment.
1Co 1:11 For it hath been declared unto me of you, my brethren, by them which are of the house of Chloe, that there are contentions among you.
1Co 1:12 Now this I say, that every one of you saith, I am of Paul; and I of Apollos; and I of Cephas; and I of Christ.
1Co 1:13 Is Christ divided? was Paul crucified for you? or were ye baptized in the name of Paul?
1Jn 4:1 Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world.
Eph 4:4 There is one body, and one Spirit, even as ye are called in one hope of your calling;
Eph 4:5 One Lord, one faith, one baptism,
Eph 4:6 One God and Father of all, who is above all, and through all, and in you all.
One church, one body and one head.
Mat 16:18 And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
Eph 1:22 And hath put all things under his feet, and gave him to be the head over all things to the church,
Eph 1:23 Which is his body, the fulness of him that filleth all in all.
Salvation is in the church and only one way to get in.
Gal 3:26 For ye are all the children of God by faith in Christ Jesus.
Gal 3:27 For as many of you as have been baptized into Christ have put on Christ.
Gal 3:28 There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.