I have one form called Watering Volume Log where users input the Ranch Water Source and Water Volume in GPM. I have another form called Watering Log where there is a Lookup field for the Ranch Water Source field from the other form. On the Watering Log form there is also a field called Water Volume in GPM. I want this field to autopopulate with the information that was inputted in this field on the Watering Volume Log form, but I can't figure out how to do this. 

Can anyone help me with the code to make this happen?

Thank you!