HOW DO I CHANGE DATES AUTOMATICALLY IN EXCEL

Hello,

Any clever person out there.

I am a frustrated administrator.

I need to forward plan with dates. Basically I enter a Date of Birth in one column (Column C) format DD/MM/YYYY I need to automatically update into another column (Column F) a date which is this date of birth plus 14 days, and in another column (Column H) this date of birth plus 6 weeks? Is there a formula which will automatically calculate these dates every time I enter date of birth?