Reading Raw Data

Hi,
I just want to confirm that I'm understanding the raw data correctly. (See below for recording -- sample rate is 250 and number channels is 8)
1st column: sample index
2nd column: ??
3rd column: CHANNEL 1
4th column: CHANNEL 2
5th column: CHANNEL 3
6th column: CHANNEL 4
7th column: CHANNEL 5
8th column: CHANNEL 6
9th column: CHANNEL 7
10th column: CHANNEL 8
11th column: timestamp
12th column: timestamp in a different format

0, -16415.32, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.008, -0.008, 0.506, 16:25:11.101, 1610313911101
1, -16331.59, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.000, 0.000, 0.000, 16:25:11.106, 1610313911106
2, -18678.68, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.000, 0.000, 0.000, 16:25:11.106, 1610313911106
3, -18996.72, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.000, 0.000, 0.000, 16:25:11.112, 1610313911112
4, -16759.54, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.000, 0.000, 0.000, 16:25:11.112, 1610313911112
5, -16066.19, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.000, 0.000, 0.000, 16:25:11.120, 1610313911120
6, -18292.89, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.000, 0.000, 0.000, 16:25:11.120, 1610313911120
7, -19193.40, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.012, -0.012, 0.770, 16:25:11.128, 1610313911128
8, -17151.32, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.000, 0.000, 0.000, 16:25:11.128, 1610313911128
9, -15914.67, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.000, 0.000, 0.000, 16:25:11.135, 1610313911135