In contemporary churches there is usually one man, the pastor, who has the job of preaching the main message, and there are others who contribute through smaller duties such as song leading, or Scripture reading. But in most first century churches there appear to be more flexibility. There was not just one man who was the designated preacher. Others shared in this task. The downside of that arrangement, was that sometimes the church services could degenerate into disorder. But Paul emphasizes in his letter to the Corinthians that order must be maintained at all times so that all are edified. This is how describes to the Corinthians what their church services should look like.
What then shall we say, brothers and sisters? When you come together, each of you has a hymn, or a word of instruction, a revelation, a tongue or an interpretation. Everything must be done so that the church may be built up. (I Corinthians 14:26 NIV).
We see in this example above that Paul expected there to be quite a bit of direct participation on the part of the church members. Some of them could apparently select a hymn on the spot, others may be cleared to give a word of instruction or a revelation. In some cases perhaps one person might even have been directly inspired to speak in a supernatural tongue, in which case God would also give someone else the ability to provide the interpretation. Participation was apparently encouraged, and yet it must have been controlled to, so that this liberty was not abused. Everything must be done in an orderly, united fashion, so that the church may be built up.