I'm not sure if I understand you correctly, but I'll try and provide as much info as possible:
From the moment you begin the game, you have 10 default pattens in your pockets (accessible via the pencil icon on your touch screen). You can use these patterns as a hat or an umbrella by simply selecting the pattern and pressing wear; this prompts you to choose between a hat or umbrella.
These patterns can also be displayed on the ground and many choose to create paths using them. If you want to do this, simply select "display on ground" instead of "wear".
If you wish to make a custom pattern (your own design) and make it from scratch, you need to talk to Mabel and she will ask if you want to make a pro design or save a design. Simply click "Make a pro design".
It's at this stage she prompts you to choose whether you want to make a shirt (prompts for further details such as sleeve length), a dress or a hat (which can also be used as an umbrella).
It costs 500 bells to make a design and the pattern must replace one of the existing 10 default patterns, much like previous Animal Crossing games.
You can then decide to display them in the shop or wear them. To wear them, simply select the pattern (assuming you made a pro design) from your pockets and select wear. If it's a pro design or a hat/umbrella, it will prompt accordingly.
Other third-party designs or patterns other players have made can be obtained by using the QR machine. This machine allows a player to scan a QR code with the 3DS camera which then asks if you wish to overwrite one of your patterns with the newly found QR pattern. You get to preview the pattern first which is handy.
The machine appears in the shop 7-10 days after you first speak to Sable, but you must speak with her once a day, every day until it appears.
You can also save your designs and export/share them by creating your own QR codes using this machine.
- Further details about Ables and Patterns can be found HERE.
- A great resource for popular QR Designs can be found HERE.