Make holes in the bottom of the tin.
Cover the bottom with a layer of gravel to improve drainage. Put some potting mix on top of the layer of gravel.
Take the plants out of their plastic pots and gently remove some of the potting mix from around the roots. Arrange the plants in the tin, putting the taller plants toward the back. Press more potting mix around the plants and push the mix down firmly. Keep the tin well watered and remember to place it on a tray to catch the drips while you water.
Excerpted with permission from <a target="_blank" href="https://www.amazon.com/gp/product/1782494596/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1782494596&linkCode=as2&tag=craftfocom-20&linkId=2daa9e104f9c40667ecdf843249d939a">Teeny Tiny Gardening</a>, published by CICO books.