Thank you for the invite Fazle!
For a very easy comparison, you can think of learning machine learning as learning to program. When you start programming, you feel the need to use if-else and then when you want to iterate over a list/array you use a loop. You already have an idea of all these functions/utilities available to you and you pick and choose and arrange all these in a manner to complete your task. If you don't know how to go about something, you check if there are library functions or modules available which kind of do the sub-task you want to complete.
Similarly, think of Machine Learning where you are aware of what you want to achieve. Then you think whether you want to use supervised learning or unsupervised learning. Whether clustering would help in this case. You will google search for algorithms which help you sanitize data. You will mostly learn on the job.
You have all the pieces of the puzzle. You have to figure out how to arrange them.
If you feel the Coursera course is too much to keep up with, you can check out this Youtube series: youtube.com/watch The first video gives an insight into what all is possible with Machine Learning.