I travel from home to different sites by the company vehicle, how to account for private kilos?

You would only include the business km's from the office to the site, so if you go from home to site then you would need to calculate the distance from home to office and subtract that from the total distance traveled.

You must keep a logbook of all the distances and places you go to.

Very helpful and will use it in future for reference.

Only a pleasure!