Microsoft SQL Server 2014 Management Studio Security Help

I wrote a database a couple of weeks ago for an assignment, the assignment for this week is to take that Microsoft SQL Database, which I wrote in Microsoft SQL Server 2014 Managment Studio. 

I am supposed to password protect the database, I have tried a couple of different things I found online but nothing has worked, so I need help trying to figure out how to do this apparently.

I also have to create a matrix to indicate the permissions (read, insert, delete, modify) I would grant to different users of my database.

I have to create at least 2 different users, and implement their permissions unsing SQL statements. 

I am willing to pay from 5 to 20 depending on the level of help I am able to get