I spent the first few months doing a lot of reading about the subject I wanted to work in. I had to find out how solar refrigeration is supposed to work and what other people have been doing to investigate it. Once I had done that (a review of the literature), I was better informed to be able to decide what aspect of the problem I wanted to investigate. Then I had to start thinking of how I was going to investigate it, what experiments I wanted to do and what I hoped the results would show. I also started some simple modelling on the computer of how the refrigeration system should work.
When you start work as a young engineer, you will work closely with more senior engineers. You will be put to work on a project or a number of projects, but told what to do – some analysis to carry out, some information to research, some testing to carry out, etc. The work will be related in some way to what you have learned at university/college, but ther will be alot of on the job learning too. As you show you can do the small tasks, you will be given bigger tasks to do and gradually to take on more responsibility for more parts of the projects until you have shown that you have enough experience and capability to take on whole projects (small ones at first). Then you will have to be able to show that you can identify the problem you are trying to solve, define how you are going to solve the problem, work out how long it will take, who and what you need to help you and then start working on it, making sure you tell mangers/clients what you are doing and how you are getting on, until you think you have solve the problem whn you can present the results.