The 'nuts and bolts' of something are the internal or essential parts of something that make it work. In a figurative sense, when we focus on the 'nuts and bolts' of something, we move beyond the superficial or unnecessary stuff and focus on the fundamental, practical elements. This is mainly used in business contexts, relating to production or just to business operations in general.

1. I read the book to give myself a better understanding of the nuts and bolts of computer coding.
2. I have the nuts and bolts of the kitchen finished I just have to paint the room next.

1. Jack could talk a good game, but he really never understood the nuts and bolts of the business which was why he struggled.
2. We managed to come up with quite a few good ideas in the meeting, but we never got around to the nuts and bolts of how to implement them.
3. Helen put together the nuts and bolts of the deal, my job was to just fine-tune some of the details.