Steps take people from one level to another. In a house, that's pretty simple. You build steps to an upstairs or from a basement to outside or from a sidewalk to a porch. Those are pretty standard step situations, with fixed heights and widths. Steps are trickier outside, in a yard or garden or on a pathway where surfaces vary and may be uneven or off level. But with planning and preparation, you can build steps almost anywhere.
Decide where you need steps and mark out a rough path with a garden hose or string line. Measure the steepness of the grade. Set a stake at the top and another taller stake or pole at the bottom. Put a string between those and level it with a line level. Measure the distance from the bottom of the lower stake to the string and the distance between the top and bottom stakes. Use those to figure the angle; a 33 percent grade, for instance, will drop 1 foot for every 3 feet of distance. Measure the angle on the side of the step area if the ground slopes both ways.
Use the angle calculation to determine how many steps you will need and how they should be set. Plan steps with risers (the step up) no more than 1 foot and preferably about 8-9 inches. Plan treads (the level part of the step) to be at least 1 foot wide. Figure out how many steps will be needed to cover the total rise of the ground and how many will be needed to cover the length. Put more steps closely spaced on steep slopes, fewer steps with wider treads or landings on gentle slopes.
Design steps to be level, even if the ground slopes up and down or sideways. Use side stones or walls to build up or hold back uneven ground on the sides of the steps. Make a short wall if there is a steep slope on one side of the steps. Build it up to match the level on the other side, using bricks or stones or the pavers you use for the steps.
Make the steps by digging out a rough step arrangement in the ground with a shovel. Dig it at least twice the depth of the step material, stone or brick. Put a layer of gravel over the dirt. Lay landscape fabric first if weeds and grass will be a problem. Add a layer of sand to make leveling the pavers easier. Start building steps at the bottom. Set the first step level and solid, then put the second step behind it so its riser is slightly below the top of the first step. Work your way up.
Build an actual step wall if the slope is severe on one side of the steps. Dig a trench paralleling the steps, put down a gravel base, then lay stones or bricks into the trench, working up the steps, until there is a solid step wall. Use mortar to hold stones or bricks if the slope is steep enough that dry stacks might slip. Add treads and risers to match the wall after it is completed.