My department's SharePoint Online site has a library holding the minutes for our weekly project managers meeting. I want to have them ordered by the meeting date. I created a column in the library to hold the meeting date. I can add the meeting date by doing right click > properties from each file in the library in turn, and adding the meeting date manually in the 'meeting date' box that now appears as a property field. 

My problem is that when I do that it sends an email notification to everyone in the department that a file in the library has changed. As there are over 40 files in the library I don't want to irritate my colleagues by having them sent 40+ notifications! So my question is how can I temporarily turn off notifications for this library while I add the info to the meeting date column?

I've tried Googling for the answer but I can't find it. Note that I'm something of a SharePoint newbie so a "for Dummies" type of answer would be appreciated!

As stated above, the SharePoint version in use is SharePoint Online (365 or 2013 I think).