UPDATED: Add Bulk Users to Distribution List in Office 365 via PowerShell (or via simple program)

I need to bulk add email addresses to a new distribution lists with a name input at the beginning of the process. UPDATE: A small program with a GUI is the only way I want this to be implemented (I recognize Powershell and some commands from the command prompt is the most common way to do this), but I realize that to make this "idiot proof" (meaning being able to hand it off to an employee or a VA) a really simple GUI/program is needed. UPDATE: I have added a mockup of what I envision as the simple GUI. I need the CSV file broken into smaller distribution lists with an option to select distribution list size. For example: I have a master list entitled "[login to view URL]" with 103,400 email addresses in it. I want to import those email addresses into multiple distribution lists created by this process/program. I want to select the input file (the master list) using file manager. I want to enter the size of each distribution list (in this example) to be 1,000 records (with a forced limit of 5,000 records per list being the maximum allowed). I next want to be able to specify the "root" name of all of the distribution lists. In this example, each of the 104 distribution lists created by the process/program (103 lists of 1,000 records, the last list with the remaining 400 records) would be named in this fashion: CHICAGO-75-MI-RADIUS-0001 CHICAGO-75-MI-RADIUS-0002 CHICAGO-75-MI-RADIUS-0003 .... CHICAGO-75-MI-RADIUS-0104 Lastly I want to be able to specify where a copy of these lists will be stored locally (again, using file manager). Once those entries have been made the "Run" button will be clicked on and then the lists will be created and stored in MS 365 Teams/Groups > Distribution Lists (as well as a copy stored locally). It appears this link has info that might assist in the underlying process (though I am in no way even remotely well versed in any of this): [login to view URL] This link also appears to have some relevance: [login to view URL] I have not done so, as yet, but will be following these steps regarding how to Connect to Exchange Online PowerShell (since I presume that will be used in whatever is created to make this process work. If unnecessary, let me know). If you have already done something like this, please let me know as that will aid in my selection of a Freelancer. Thank you. Duane