Set you Maximum Grade to match the automatically generated Total of Marks.  Things will still calculate correctly if you don't, but you will get some strange numbers (e.g. .82 instead of 1) which confuse students and generate lots of questions for you.

For greater exam security, you can shuffle all your questions or some of your questions.  This increases exam security with randomized questions only when you are pulling questions from more than one category (e.g. Chapters 1, 3, and 4).

To Shuffle all the questions in a quiz, tick the Shuffle at the top right of the page.

To Shuffle some of your questions, you will need to add a Page Break and create Section Headers. Each section has an option to Shuffle which only applies to the questions within that section.

You can create regular page breaks every so many questions (recommend no more than 4 or 5 questions per page because student answers save each time they click Next to move to the next page) using Repaginate.

Or you can use the page break options  to set more controlled breaks (e.g. between multiple choice and essay questions).

The top section header can be added by clicking the edit pencil found below the Repaginate button.

To add a Section Header further down in the quiz, go to the page break where you want the header to be added, then click the Add. 

From the drop-down list, select A New Section Heading

To edit the New Heading, click the edit pencil, type your new heading label, then press Enter to save it.

If you have questions you wish to remove from the quiz, you can use the Select Multiple Items to remove sets of questions.