How do I add custom order fields for users to fill out at checkout Drupal 7 - Commerce

I have 2 fields related to the order. one is radio button where user selects Pickup, Delivery. the other one I won't mention as it might confuse some people. I want the user to select which one they want at checkout. How do I do this?

I've added the fields the order. admin/commerce/config/order/fields. They don't show up on the checkout, but they do show up when the admin tries to edit the order.

I tried setting the fields as required, but the order gets created with these fields blank (this is a bug).

There are no options to add these fields on Checkout Settings admin/commerce/config/checkout.

I am not looking to add fields inside Billing Information nor Shipping Information.
I was able to solve this problem using Commerce Field Group.   What you do is: 


create the fields you want.
create the field group.
put the new fields inside the field group.


Then


goto the Checkout Settings (admin/commerce/config/checkout) and add the group inside Review