An example will make you understand the situation better. Suppose, you need to open Notepad and Calculator almost every time. We will create a batch file, so that, on double clicking the batch file both programs (say Calculator and Notepad) will open at a time.
Open Notepad. Write the code:
It will look like this:
Now, click File > Save as.. and save it with the name you like with bat extension. For example, we have saved it as Notepad_Calculator.bat. Do not forget to change the file type from text files to all files:
You will get the batch file, just double click to launch the programs at a time: