How do I debug step by step

Do simple thing: before you start intensively using some new IDE, or some other tool, such as advanced editor for some data or media type, perform extensive study of this tool. As a minimum, scan each and every menu item in all modes and get a good idea on what it does. You don't have to remember anything, but at least you will be familiar with what you are dealing with. In more general way: don't jump immediately to what you consider as your ultimate goals. First, sharpen your tools and learn how to sharpen them. Isn't that elementary. There is nothing better for saving time than investing… good amount of time for sharpening your tools.

Specifically on Visual Studio debugging: everything related to debugging is located under the top-level menu items "Debug" and "View". Don't forget context menu in Solution Explorer. Also note that debugging is done in a different Visual Studio mode. That is, to get to debugging mode, you have to… start debugging. Start with F10, or more productively, set at least one breakpoint and press F5. And so on…

—SA

cough look at f10, f11 for example - you can also set 'break points' on lines of code, use f5 and the execution will stop when (hopefully when, not 'if') you get to a breakpoint ... you can then use various windows to inspect the content of variables to see what values they contain

This is a valuable skill, so learn up on it now :-) in the old days <sigh>, we had to write/dump our variable contents to the console window to debug - ie, you would insert

WriteLine("The value of x is {x}", x); 

for example if you needed to see what 'x' contained after you'd modified it.

Usually if you have issues with your code, you can identify a few key areas where values could be manipulated incorrectly, and hence causing the error. In this case, as the other solutions mention, is to add a breakpoint in those areas. Then, whenever you start debugging, you can identify what those errors are as debugging will halt at those breakpoints. It can sometimes be tedious to start debugging, but it usually resolves errors much faster than glancing at the code.

F10 in Visual studio will start the native debugger.