Managing personal Outlook.com account settings, security, and privacy
Since your @msn.com account IS an @outlook.com account, it was unnecessary to create another account. You could have logged into Windows 10 with your existing account.
You can merge two accounts using a tool like Windows Live Mail. It's fairly straight forward. You can't merge OneDrive allocations, however. You can use both allocations separately, though, keeping some files on one and some on the other. One you can sync through the OneDrive folder on the PC, but the other you'll need to use through a web browser.