Please Help - How do I populate values in checkboxes

Please Help - How do I populate values in checkboxes

I'm trying to populate the values of a checkbox field (EstRequest.Send) with data from another form with criteria. My source is team_member[role == "Contractor"].name. The destination form EstRequest has 2 fields: EstJob & Send. I need to be able to check one or more names and send email to each on submit.

1.How do I fetch all the names of Contractors and assign them to the values list of the checkbox?
2. How do I send an email to each checked value?

My app is "RAD Project" and is share to support for edit.
Can you please show me how to code this? Many thanks.
Frank