“They stood these men before the apostles, who prayed and placed their hands on them.”
In the Jerusalem church, seven men were chosen to see to the needs of all the widows among them. The apostles set them apart by prayer (part of their work, v. 4) and laying hands upon them.
Were they deacons, in the official sense? It’s a big controversy. Perhaps because we get hung up on titles and positions. They served the church. That is enough. (But there was an official ceremony!)