Can someone explain how to fill out the form to transfer the GI Bill to dependents?

I retire in two years and want to split the GI Bill between my 9th grader and 7th grader and wife. So for my 9th grader do I put the dates as 2013 to 2017 with 12 months of tuition? The 7th grader 2015-2019 with 12 and my wife what if I only know she wants to go to school sometime in the future?

Anyone know who to ask? I think I understand the eligibility and all

I am a part time Reservist