You question is how to better understand and debug these errors. Well all I can say is, look at the actual error message output, it will normally include a line number. Now you can look at the specific line of code and see if you can spot what is wrong.
I don’t know if the formatting of the code in your question comes from a failed attempt at pasting it into stackoverflow.com or if that is also how you are working with it, but you should format it properly and that will help with spotting problems. For example, when I formatted your code above straight away you can see an additional closing curly brace.
Once you have the actual error messages and line numbers etc. your best bet is to google the error and try to understand what it means. Once you have exhausted that avenue come back here and formulate a specific question showing exactly what the error message is and the code you are running. Avoid grouping many problems into one question like you have done here.