Coding

So I'm not sure if I'll be able to form a question out of this but essentially I have a major issue with coding. I find myself able to generally understand what people are trying to do when they are coding for themselves. However, when I sit in front of the screen ready to type I never know where to even begin. Because of this I find it hard to do most labs and and fill in the space type worksheets. This block has been hard for me to overcome and really I haven't truly gotten there yet (although I guess that wasn't much of a shocker). I know there is a general format to follow such as after you start a class you add the instance variables, the constructor, modifier, accessor, and then the toString method. But I don't always know what explicitly to write. Another thing is I feel that the default and initialization constructors do the exact same thing so why have them both instead of just one? And I feel the modifier is too. So I guess my question could be why do we need those 5 methods I mentioned?