Here is a snippet from a program I ran at our open house. Note the M291 to designate make the sub-spindle C-axis and the M290 at the end to make the main spindle C-axis.
( OPERATION 17, MILL HOLES )
( SIDE 1 LIVE )
( TOOL POSITION 5, .5 DIA. SPOT DRILL )
( CS#6 - XY PLANE )
( SUB SPINDLE )
G28U0.
G30W0.
G0G53B0.
T0732
M35
M135
M291(C SUB)<----------------------------------------
G0G28H0.
G97S6000M3P12
G55
M8
M108
G18
M110
G0G98Z-.1C0.
X1.4242
G83X1.4242C0.Z.6R0.F25.
C90.
C180.
C270.
G80G0Z-.1
( OPERATION 18, MILL CONTOUR )
( SIDE 2 CHAMFER )
( TOOL POSITION 5, .5 DIA. SPOT DRILL )
( SUB SPINDLE )
G0G98X.2977C1059.284(M8)
G50C339.284
C0.
G112
G1X.2785C.0527F200.
Z.04F20.
G2X.3264C.0377I.0045J-.0195
X.335C0.I-.1632J-.0377F35.
X0.C-.1675I-.1675
X-.335C0.J.1675
X0.C.1675I.1675
X.3264C.0377J-.1675
X.2964C.0137I-.0195J-.0045
G40
G1Z-.1F200.
G113
G0X.2977
( OPERATION 19, MILL CONTOUR )
( SIDE 2 CHAMFER )
( TOOL POSITION 5, .5 DIA. SPOT DRILL )
( SUB SPINDLE )
G0G98X2.1998C725.911(M8)
G50C5.911
C0.
G112
G1X2.1881C-.1133F200.
Z.745F20.
G2X2.1587C-.0891I.0047J.0195
G3X1.1467C.3515I-.3672J.0891F35.
G2X.7029C.5734I-.0629J.159
G3X-.7029I-.3515J.1387
G2X-1.1467C.3515I-.159J-.0629
G3C-.3515I-.1387J-.3515
G2X-.7029C-.5734I.0629J-.159
G3X.7029I.3515J-.1387
G2X1.1467C-.3515I.159J.0629
G3X2.1587C-.0891I.1387J.3515
G2X2.207C-.0744I.0195J-.0047
G40
G1Z-.1F200.
G113
M290(C MAIN) <------------------------------------------
G0X2.212
G28U0.
G30W0.
G0G53B0.
M9
M109
M5P12
M34
M134
M114
G54
M54
M30