Where did the concept of Christians attending a church building come from? Christians attend church on Sundays, they sing, listen to a pastor speak, etc. 
When did such a concept first appeared? 
Did the early Christians practice this?  or is this 'attending church' a medieval tradition from the Roman Catholic church?
In the earliest days of the church Christians met in the Temple in Jerusalem and in each others homes. (Acts 2:26)

The Apostles would preach in the Jewish synagogues, often evangelistically, but sometimes even at the invitation of the other Jews. (See Acts 13 for example)

They would meet in lecture halls, such as the Hall of Tyrannus in Ephesus. (Acts 19:9)

The New Testament doesn't mention purpose built church buildings, and in the New Testament era the most common meeting place for Christians was in each others' homes.

The earliest known church building is the Dura-Europos church, which was converted from a regular house in around 233-256AD.