I explain the basics of reading standard notation starting here.

https://www.guitartricks.com/lesson/10272

If you are completely new to using the musical alphabet I suggest starting at this earlier tutorial.

https://www.guitartricks.com/lesson/11078

And if you are looking for beginner material to practice you can use these tutorials of simple melodies that gradually cover all the strings in the basic positions.

https://www.guitartricks.com/lesson/11107

https://www.guitartricks.com/tutorial/1014/

https://www.guitartricks.com/tutorial/1024/

Hope that helps!  Please ask more if necessary!