Add Values Across Multiple Sheets

Hello Excel Geniuses,

I am building a workbook where worksheets will be added over time. Each worksheet will be in the same format and the values I need will be in the same cells. I would like to automatically sum certain values, based on the name of a specific cell in each worksheet and update the master sheet every time a worksheet is added. I would love to do it with a formula if possible, but am open to an "Update" button. I have attached a sample workbook to explain better. Thank you in advance for all your help!!!!