I've just bought a house with a large, but sloped garden.
What I would like to do is separate the one slope into 3 flat surfaces.
Does anyone have an idea for the best way to do this?
Does it slope away from the house downwards or upwards? If you terrace a slope that is sharply upwards from the house, you end up facing a wall. If it is only a slight slope you can put in a few steps. A big slope might need a meandering path. Have you a photo giving an idea of size, slope etc?
Depending on the size of the slope you could use brick walls or sleepers as retaining walls. Try and measure how much lower or higher the slope is from the level area and you can work out the height needed for the walls. If using sleepers they will need to be pinned. Bricks should be engineering quality And the wall double width.
Does not look too bad from that photo. Have you investigated that heap in the corner? Could it be an old compost heap thats been grassed over? If you get rid of that heap, it just looks as though you could screed it almost level.
If you're looking for ideas, there's a garden/nursery in Devon called 'Wildside' with some lovely ideas for planting slopes
I would follow hogweeds advice and investigate what's buried underneath those mounds towards the back of the garden. The soil shouldn't be heaped up like that by the fences, it will rot the timber.