You can use any tools you want, including UML. Don't let fashion tell you which tool to use. The important thing is: the tool should be useful to you, and facil

You can use any tools you want, including UML. Don't let fashion tell you which tool to use. The important thing is: the tool should be useful to you, and facilitate your work in some way, and not burden you. However, I would suggest that you start at a lower level that has little to do with formalized planning techniques, since you seem to have trouble answering the most fundamental questions. (This is no criticism: fundamental questions are often difficult to answer). The following technique is based on the idea that you only understand something if you can explain it to someone else. Write down your thoughts about your software project in a project diary where you explain your work to an imaginary person. What you are doing, why and how,etc... Two to four sentences a day are enough, don't pressure yourself to write a lot, but do it. Thoughts are often not as clear as we think they are. Putting words on a page forces you to clarify your ideas. From this internal dialog, new questions will arise and new needs. Maybe you'll find out you need a complex inheritance structure in Java and UML could help you document that. Maybe you'll find out there is no need for that. But tool choice comes after answering the fundamental questions. The rest is just googling.