Complex sentence: He went to Germany as an Erasmus participant and was an assistant at Theaterperipherie in Frankfurt, performing in the plays "Waiting for Godot" and "Maria Magdalena" there.
Split into simpler sentences: He went to Germany as an Erasmus participant and had been an assistant there at Theaterperipherie in Frankfurt. He performed in plays like "Waiting for Godot" and "Maria Magdalena" there.