try and chose stones of the same type so that it look more natural. prefereable of different sizes too. the stone should be buried 1/2 - 2/3 to anchor the rocks in place. but as yours is a modest size I doubt if you will be standing on them.

go for plants that are described as alpine rather than dwarf. but doo check on their typical size as it is easy to pop plants in that then take over. check their final size as some especially conifers don't have an upper limit just 2ft in 10 yrs so in 20 yrs it will be 4ft etc. [I've fallen foul of that yrs ago]

then its down to personal choice.

And one other thing - rockeries need as much sun as possible, because the type of plants growing on them are sunlovers.

What is the site like at the moment? Is it level, out in the open, accessible from all sides? What surrounds it - lawn, flower bed, paving?
For a brand new rockery 2.4m x 1.2m is quite a chunk of land to cover in rock - to look in any way natural you will need to allow almost the same area in rock (I would suggest at least 60-70% plus smaller stones and gravel), otherwise it will be a garden bed with a few (big) stones.
Do an image search on the Internet (or get an old-fashioned book from the library) to get ideas of what you want to achieve.

Good rockeries have the stones arranged to look like natural rock strata so try to avoid a lot of random ones.

Thank you for your comments very helpful the area is a raised bed , it is flat ,I noticed people say sunny area ? Mine is under shade ant tips ?

Yea, don't build a rockery there! I've said it jokily, but actually, I mean it - 99% of plants grown on rockeries are alpine type plants which require full sun and full exposure. You'd be best off planting up shade planting straight into the ground instead - if you want suggestions for that, just ask...

Yes please bamboo

there are plants that will cope with dry shade and there are some that will look right in a rock garden/rockery.
I say 'dry shade' because, generally, rock gardens/rockeries are designed to be well-drained but if you have underlying clay then it may not be dry.
If the rockery is open on all sides then some part of it is bound to be in shade at some point in the day.
If you have damp shade you could go for ferns - think of the plants around a rocky waterfall.
There are lots of 'natural' rock garden effects without sticking to alpines.

Ok thanks urbanite ?

Mendum, in order to give a list of shade planting, need a bit more info please

1. what kind of shade is it under - is it shade from a fence or a house?

2. Is it in shade all day, or does it get a couple of hours at some point?

3. Or is the shade created because its under trees?

4. Any idea which way it faces (east, south, whatever)?

5. And you say its raised, raised how - is it held up with wood or stone, in other words, is it a raised bed you've created? If so, is it open onto soil beneath, or does it have a solid bottom of some sort?

Hi Bamboo
The garden is east facing
It dose get some sun but it is shaded with over hanging trees from both neighbours oak trees
The area is raised with railway sleepers and soil,it was built for a veg plot but we just don't have time to maintain it so we want to change it to a rockery
Hope this helps

Okay, I'm going to assume two things - that the raised bed is open onto soil at the bottom and not onto concrete or other hard surface, and that the measurements you've given mean 2.4 metres long by 1.2 metres wide from front to back. I'll also assume the area might be somewhat dry if there are oak trees close enough to provide shade.

Here's a list of plants you could use in that situation:
Larger shrubs:
Mahonia japonica
Mahonia aquifolium
Elaeagnus varieties
Box (Buxus)
Sarcococca varieties
Hypericum 'Hidcote'
Ribes sanguinam

All are evergreen barring the last two which are either semi evergreen or, in the case of Ribes, deciduous.

Ferns: Asplenium and Polypodium will tolerate drier conditions.
Perennials/ground cover: Any kind of Lamium, from Lamium galeobdolen to the smaller, ground covering types such as L. 'Beacon Silver'. Saxifraga umbrosa; Heuchera Red Spangles; Heuchera 'Midnight Rose' (nearer the front so it might catch some sun), Campanula portenschlagiana (sometimes still sold as Campanula muralis), Geraniums such as 'Wargrave's Pink'.

There are more, but other plants that don't mind shadier conditions aren't so keen on dryness at the roots - if its not as dry as I'm assuming, then you can have another list (!) but as you've got to look them all up, I'll leave it at that for now.

Bamboo thank you soo much??