If you have a rough sketch of your design the first thing you have to do is add more details to it.
That’s like,
What fabric you are going to use.
What size you are going to use.
And how long or short, how tight or loose to your body.
If you are adding pockets, zippers, buttons, and you must decide everything before you go to the next level.
If you know about Fashion designing It would be easier,
Otherwise, you better ask for help from a professional fashion designer.
After the Fashion designer part, You have to send those details to a pattern maker.
With all those details, the pattern maker job is to make a flat pattern sample of your design.
When you get the sample pattern you will have to make a sample garment from that
and make adjustments and send back to the pattern maker to create the final pattern.
After finish the final pattern you can ask the pattern maker to size grading as well
Now, all you have to do is gather your materials and send them to a good sewing company
This is a simple version of starting a clothing brand.
As a beginner, you can start simple.
If you need any help, feel free to contact us.
Watch this simple video, You will get an idea of what I was trying to say.