Placement of buttons for Previous, Next, and Save Draft actions

1. Where should a next button be?
2. Where do I put the save button in UX?
3. What are secondary action buttons?

Where should a next button be?

The next button should be at the bottom of the page, preferably on the right hand side.

Where do I put the save button in UX?

Considering that your users will typically navigate to one category, make a change, then click Save Changes, I think placing the button at the bottom/left is best. If your users were frequently making changes across multiple categories, then you'd have a good argument for placing the button at the top.

What are secondary action buttons?

Secondary action

Secondary buttons are the 'go back' to the primary button's 'next', or the 'cancel' button to the 'submit' button. Secondary buttons are the alternative we give users to the primary action. Two variations of secondary actions next to primary ones.