What's the meaning of the columns of the merged vcf files?

[ligot21]

Thank you for your pipeline first. I am confused about the output. For example, if "normal_sample" and "tumor_sample" are used as input. The merged vcf file will have four heads named tumor _sample, normal_sample, TUMOR, and NORMAL. Which one should I refer to if I want to know the mutations in the "tumor_sample". And what's the meaning of "TUMOR" and "NORMAL"? They have more mutations and don't seem to be duplicates of other columns.