I started a project Instagram-Social Media Manager that has a fixed price (3 milestones) and lasts 3 months. I comment and like posts of some similar accounts and so, I increase engagement. Since I don't have Upwork experience, (I had only one short project in past), I am not sure how and when I should submit my work for payment. Do I have to upload some screenshots of my work or ?
Once hired, freelancers can submit work through Messages in the dedicated message room created for a specific contract. Also, on Fixed-Price jobs, freelancers are advised to use the submit work link on the contract details page in order to share the final product with their client and at the same moment request payment. You may read more about Fixed-Price Protection. It is always good to communicate with your client and discuss the terms of further engagement on the contract in order to avoid any misunderstanding.