The simplest way is to press the TAB key. Pressing the TAB key will automatically record your answer and move you to the next question. Some questions require that you select one or more answers from a list of predetermined choices. Then press your left mouse button. If you change your mind, simply click on one of the alternative answers.
Some questions allow more than one answer.
In that case, select all of the choices that may apply. Some questions require more than one word answers. In that case a scroll text box will appear. Make sure that your cursor is inside the scroll before you start typing. These boxes have a limited amount of text that they can accept, so be concise.