Some columns report country total data. Transform these columns into per capita data. You will not need the original columns (including Population) for further analysis.
In the data you have, some columns contain the Total of a variable (or measure) by country. For example, you could have one column that has for each country the "Total meat production in kilograms". What they are asking you to do is to calculate a column with the value per capita, i.e., the amount of the variable that is produced or consumed by one person in the country.
So, if you have "total meat production in kilograms" they want you to calculate "meat production per person in kilograms". To do this you need to find a column with the total population of the country, and the divide the total value by the population to get the per capita value.