There's some guidance in the first few rows of the file, one of which is:
"## RECSUse this file to upload product display information to Recommendations. Each product has its own row. Each line must contain 19 values and if not all are filled a space should be left."
You only have 11 columns in your file; typically would just see customers adding empty columns with headers entity.custom1, entity.custom2, entity.custom3 etc etc to reach the required number