How to draw multiple line curves?

Many a time, we require multiple line curves. This is required to show the variation of one parameter against the other. If you show graphically, it is always easily intelligible to others. Once you learn how to do this, you can apply it for your research work. I learned it from my teacher in masters. Each and every time, I use it, I say thanks to my guide.

 Let us consider, we are testing four fuels in a diesel engine such as diesel, BD1, BD2, and BD3 against various load conditions such as 5, 10, 15, and 20 kg respectively. Now, you are asked to draw a curve of brake thermal efficiency (BTE) (or you may say any parameter) versus load (or you can say against any parameter) curves for these fuels when utilized in the diesel engine. First of all, you need to know how to open excel sheet!!! Then what is the steps you need to follow are given step by step in the video. https://youtu.be/ZIbO1Skfkc4