To convert kgs to grammes multiply by 1000. I've generated some hopefully helpful examples randomly below, as with most random sentences please excuse the repetitive and occasionally comic outcomes.
You have 530 kgs of rye but you need to know how many grammes that is. To get the answer multiply by 1000 which gives you 530000 grammes.
In 930 kgs of carrots there are 930000 grammes, to achieve this take 930 and just multiply by 1000.
You've got 540 kgs of potatoes but someone only wants to buy that in units of grammes, to change the units multiply by 1000. Now you have 540000 grammes.