Suppose you face a delay in your first milestone - how will you deal with this?

First and foremost I would ensure to keep relevant stakeholders engaged with constant communication on the reason why I failed to reach the milestone. I would also apologize for the same and communicate a timeline when I would be able to deliver the same. Secondly, I would do a root cause analysis on why I failed to deliver the milestone and based on the issue, I would get the relevant resources to address the problem. If it is out of my team's control, I would communicate with the relevant team to see to it that we work across the two functional teams to solve the problem.