A garden zone does not get confusing when you talk about it in normal conversation, because it refers to a space that has a specific intent, such as a place to stroll or to sit or to plant or to keep for the tools or a section of lawn that is open or an area that helps to screen a view or an area where someone can go to relax in the evening. Before you think about plant names or color or ornament, zone plans help you figure out what the garden needs to do in the outdoor spaces.
You do not need to have great drawing skills. A rough layout map is what you need. If you have graph paper, then you can use it. If it is easier to use regular paper, then you can do that, too. Start by marking any fixed structures. Start by outlining the house, the doors, the windows, the boundary wall, the current trees, the edge of the patio or a walkway, the stairs, the outbuilding, or any existing pathway. Even an uneven drawing will help you think in some way. What you are trying to do is not make a work of art. The real purpose is to not think about the entire garden in your mind.
After you mark your fixed items, draw in a couple general outlines of the big garden zones. Your zone for seating could be a rectangle that is near your patio, or it might be a free-style oval near a quiet nook. The planting zone could line a boundary, follow a curved edge to a lawn, or sit adjacent to an entry zone. Your walking zone should link between the areas where people will actually walk, so that includes doors, gates, seating zones, tool sheds, compost bins, etc. If you are not comfortable with a route as you see it on paper, do not think you would actually want to walk the path in your garden if it were there.
One of the problems that might arise at this stage is that each zone ends up too small. If you try to put a seating area in, several planting areas, a meandering path, a focal feature, a lawn, plus storage in one small yard, you will have a sketch that is full even if you have not decided what you want in there. Provide some open space for each zone. A path needs to be wide enough to walk. A seat requires space around it. A planter must be deep enough to accommodate plant height, mature spread, mulch, and room to work in there.
If you have a piece of tracing paper, place it over your initial base map or draw your sketch up three times on a small scale. On the first, make the planting areas wider and have a smaller lawn area. The second option will keep a larger amount of open space and place the planting along the sides. The third try at it will show if you can use a much stronger path plan that will run from the entryway, to the seating area, to the view. By comparing the options, you learn more than by trying to adjust one map over and over. You are also able to see easier the one option where the overall plan is balanced.
While you draw the map, think about views you will get from the most popular places. A zone next to a window might need a less intense plant selection, while one tucked in the backyard will need less intense planting. A focal feature needs enough space around it to attract attention rather than being tucked in between many other features. A border by a seat needs more plant texture and year-round interest, while a tight side-path might only need simple edging and no-maintenance ground cover. You can work those types of choices out more easily once you see the zones on paper.
Your first zone sketch is complete when each of the principal areas has a definite purpose. You need to be able to stand over the sketch and point to the plan and say there is a place for walking or a place for stopping to watch or a place for a plant bed where the plants can grow or a place where the garden tools can go. Your lines do not have to be pretty. What is important is that the garden is not an indistinct open space anymore. It is now a collection of workable outdoor spaces that can be worked out a bit more later.