A slopegraph will have one Measure on the Rows and one Dimension on the Columns. Lines are what take up most spaces in slopegraph. Therefore, it is used to when you want audience to focus on changes or difference between categories.
Opening the Sample Superstore dataset:
Double-click Sales or drag to Rows
Double-click Order Date or drag to Columns
Select Entire View from the Drop down box (optional)
Add Order Date on filters (Year) and select the two most recent years
Move State to Detail
You now have a slopegraph.
Using Measure Values field
Opening the State of America Rankings data:
Drag Measure Values to Rows and Measure Names to Columns
Move Measure Names to Filter. Select only 2012 Ranking and 2013 Ranking
You will have the following canvas.
Change Marks card to Line. Create a calculated field: