If you would like to know how the apostles and early Christians would have called on His true, original (and only) name, Yâ-hwéh Yâhuwshúa`, and how they would have rejected the pagan traditions in most congregations today, you should read from
www.yahuwshua.org and also study the scripture translation the Purer Scriptures for the REMNANT (PSR) downloadable for free there.
After skimming through the above responses, it seems most have recommended some of the writings that I have read to get more information on the early Christians. However, the main thing the truly faithful early Christians would have done is profess the true name of Yahweh, and the name of the Son, Yahuwshua, as well as truly live for Him, rejecting the foolish traditions of man.
Below is an excerpt from the Glad Tidings of the Truth ("gospel of the Truth") from our PSR translation).
How do name-ignorant Christians fit in?
All the spaces are His offspring; they knew that they branched from Him as children from a perfect/grown Man. They knew that they had not yet received the Image nor yet accepted the name, of which the Father procreates every one. During that time period, if they accept the Image of His recognition, though they are truly in Him they do not acknowledge Him. [YirmYâ´huw ("Jeremiah" 5: 10-14] But the Father is perfect: He does know every space which is within Him. If He pleases, He manifests anyone whom He wishes by giving him the Image and by giving him a name, when He does give him the name to Him, and causes him to come into existence (’iysh) [meaning of Yâ-hwéh]; [YchezqË´’l ("Ezekiel") 18: 5] those who have not yet come into existence are unrecognizant of Him Who created them. I do not say, then, that those who do not yet exist are nothing. But they are within Him Who will desire that they exist when He pleases, like the event which is going to happen. [Romans 8: 19]
When the Father manifests His hidden Self to us for us to pronounce His name [~Yâ-hwéh Yâhuwshúa` (Yâ-hwéh - the eternal name of the Father and Son) Yâhuwshúa`- the hidden (secret) name of the Son] and for us to also perform His works (which are the Affectionate Love of the Father, demonstrated by fulfilling the two greatest commandments), He calls us by the name which He has given to us, and (that is how) we (have) come into existence. We can only acknowledge Him by calling on His name and doing His will.