Complex sentence: Before Lupe Tijerina had come to the group, Homero Guerrero and Samuel Zapata had made a recording before Lupe in the company of Discos del Valle, that was the start of Cadetes de Linares, however they still remained a local group.
Split into simpler sentences: Before Lupe Tijerina joined the group, Homero Guerrero and Samuel Zapata had made a recording in the company of Discos del Valle. That was the start of Cadetes de Linares; however, they still remained a local group.