How to manually create own calendar

[MyStix01]

Hi,

I'm not sure if this is possible, but I've been trying to create my own calendar.

So attached is the spreadsheet and format I have created.

Basically I just need a formula under the highlighted cells that will automatically feed in the dates for the month.

So ex. If I like input the month I'm currently in under cell B4, the formulas on the highlighted cells should then be able to automatically populate by being able to identify as to which day the first day of the month would fall, and which day of the month it will end.

Hope this makes sense and I hope this is really possible. Thank you! Thank you!