Any wide shallow trough will do.  It’s quite trendy to go for stone ones but they can be quite expensive.

Choose smaller compact plants in different shapes so they’ll contrast nicely and maybe have one or two trailing ones.

Put the container on bricks before you start to make sure there’s no waterlogging.  Make sure you do this first because once planted, it will be too heavy to move

Put a base layer of stones about 2.5 inches deep at the bottom for drainage.  Then fill with potting compost up to about 5 cm (2 inches) below the top

Put the odd rock or slate on the edge to create a natural rock look and put your alpines in place (still in the pots) to see how they’re going to look

Once you’re happy with the arrangement, tip them out of their pots and plant so the rootballs are slightly above the compost

Finish with a dressing on chippings or smooth gravel to set off the plants and fill the container to the rim without completely covering the plants (this is why the rootball had to be slightly above the plant mixture)

Enjoy!