Here is a step-by-step walkthrough of how I make a decoration on the front of the knife sheath.
You can see pictures of the different steps as well as an explanation of how I do it.
Click the arrow on the right to go to the next step

I sew a sheath in the usual way and make it completely finished. See possibly the guide to sewing a knife sheath.

Before I start making the pattern on the knife sheath, I wrap the knife in a thin layer of plastic film Vita Wrap. I do this to protect the knife from moisture that can later seep down through the leather when I work on the pattern. Before I start making the pattern on the knife sheath, I wrap the knife in a thin layer of plastic film Vita Wrap. I do this to protect the knife from moisture that can later seep down through the leather when I work on the pattern.

Then I must have found a suitable pattern. You can draw your own pattern, or you can find a pattern on the internet - there are plenty to find. If I use a pattern I have found on the web, it is easy to adjust it in Photoshop

I draw the pattern onto a piece of food paper. It is easy to transfer to the leather and adjust it so that it is placed where it needs to be.
I cut the pattern so that I can easily see where it should be placed on the leather.

I draw the pattern onto a piece of food paper. It is easy to transfer to the leather and adjust it so that it is placed where it needs to be.

I cut the pattern so that I can easily see where it should be placed on the leather.

Before proceeding, I moisten the leather a little with water. It should not be soaked, but just moistened enough to clearly mark the pattern in the leather.

Now I can put the pattern on the leather. I attach it to the back of the scabbard with some small pieces of masking tape so it doesn't move when I work with it.

Now I can transfer the pattern to the leather. I stamp the pattern into the leather with the tip of my modeling iron. You have to be careful not to press too hard so that you go through the pattern paper. Then you run the risk of the whole pattern shifting and becoming crooked. You don't have to press very hard for the pattern to be visible on the leather.

When I have gone all the way around the pattern, I can take the paper off again. The pattern is now very clear on the leather.

Here you can clearly see the drawing of the pattern on the leather.

Now I have to start cutting the pattern itself. For that I use a Swivel Knife. It is a strong blade of approx. 3 mm thickness that is mounted on a shaft that can turn. You hold the handle with your fingers and can thereby easily turn the knife so that you can cut both straight and curved cuts.

Before I can start cutting the pattern, I sharpen the blade on a leather strap. It is very important that the blade is super sharp when cutting. If it is dull, it can fray the leather on the edge and the pattern becomes ugly.

Now I can start cutting the pattern. I hold the swivel knife between my thumb and middle finger and hold my index finger in the hook at the top of the knife. I hold the knife at an angle and cut with the edge of the blade. At the same time, I angle the blade so that the edge of the groove is perpendicular. It gives the nicest cut

And then it is "just" to cut the entire pattern. The leather is still moist so the knife cuts easily into the leather. You must not press too hard and thus risk cutting all the way through the leather.

When the pattern is cut all the way around, I have to build up the pattern. For that I use a brush as shown in the picture. It is a so-called "background brush" and consists of a checkered pattern

I moisten the area I want to work on with a sponge. You don't need a lot of water as only the upper leather needs to be wet. I take a small piece at a time, and that way I can work with the pattern over several rounds and I don't have to worry about getting it all done before all the leather dries.

In normal brush work, you will hit the brush with a hammer and thereby bring out the pattern, but since the scabbard is round, it is difficult to use that technique. Therefore, I press the brush into the leather. I press the brush down very close to the pattern and thereby achieve the desired relief effect

I first make the entire pattern on the outside all the way around and you can already see how the relief effect emerges.

Now I work my way into the pattern itself and make the places that need to be brushed with the background brush. It can sometimes be a bit small and you may need a smaller brush. I myself sharpened a brush so that it is half the size - it makes it easier to get into the small corners of the pattern

Then all the brush work is finished and you can now really feel the pattern - even if it is still a bit "flat" and boring.

Now I can start working on the pattern itself. I do that with the modeling iron. I first work with the areas that need to be marked clearly and drawn forward. Here, too, I moisten the leather in the area I am working with. It also makes it easy to emboss into the leather.

After this I can start working on the various details of the pattern. Here it is a small leaf that is being processed. I always have the original pattern lying around so I can get all the details onto the leather.

And again... then it is "just" to work your way through the entire pattern. How many details you want to include depends on how long you want to keep working on the pattern. When the pattern is completely embossed, I go through it one last time and finish by polishing it up with a soft cloth. This means that the sharp edges that may be straight are rounded off and the pattern appears fine and smooth.