Add a little water and mix into a dough (probably sticky!)
Take small amounts of the dough, and put on top of a stew that's cooking. Make sure the dumplings are not too big. They will get bigger (as the flour is self-raising). So you want them teaspoon sized before cooking. It doesn't matter if they are irregularly shaped. The dumplings must rest on top of the liquid as far as possible. Do not push them under the liquid or they will get soggy.
The dumplings will need about 30 minutes cooking, so add it 30 mins before the stew is cooked.
Other ideas
Adding a teaspoon of horseradish sauce is rather nice!
You can use different liquid instead of water, say milk, or beer.
Suet is animal fat (not dairy fat). This recipe is therefore non-vegetarian. However, you can use butter instead.