Hello,
My name is Vlad Markov.
I'm "crafting" software more then 17 years with 5+ years of experience in Mobile/Web.
Each project I divide to milestones like this:
1. Define project specifications.
2. Writing and approve documentation.
3. Prototyping and first demo with main functionality.
4. Finalizing project and second demo.
5. Fixing some issues/bugs and deploying project for customer.
Actually, each milestone should be payed after completing.
Additionally, I few days ago made project depended on Private Instagram API and could really fast provide working solution for you.
Link to this project: https://www.freelancer.com/projects/need-you-develop-some-software-12585295/
If you have some questions, please ask me.
Sincerely,
Vlad.