1. what to mine and how to mine and what to expect. (I am unclear on where to start)
Started from you reading about Mining types (like Mining use hardware or Cloudmining), Pools of Mining. 2. I also want to know how to find out the hash rate of a device.
2. you can go to this : https://whattomine.com/4. Suppose I start mining coin 'A' and then I want to mine coin 'B'. Is it a good thing to switch? Is is even possible to switch like this?
4. Yes, maybe if you think a coin 'A' profit is low than a coin B.Reagrding Question 1 I will go for the use of Hardware and than maybe pool later. I don't have any plans for going for Cloud Mining whatsoever.
2. Thanks for the source. Also if you can enlighten me about the temp and clocking the device? I have read somewhere that the clocking to device also effects whattomine
(You see what I did there? No, Ok I will stop) 
4. My point in this question was what changes will I have to make if i want to shift from one coin to another.
2: temp and clocking depend on exactly what 'device' you're talking about - ASIC, GPU, CPU are all very different, but could be used to mine, depending on what algo you're aiming at. Each GPU has it's own optimum clocks, which you'll have to test.
4: Ditto. Depends what hardware you're running to begin with. Might be as easy as clicking a toggle in your pool settings, or might need you to trade/buy a coin that you can't mine with your hardware (eg: you have a gpu farm but want BTC). Switching is all very well, but there are many hidden variables, such as pool payout levels, time taken to setup and optimise, and the fact that yesterday's great idea might be todays awful one, because everyone else has done it too.