This is done within Creator. 

To export a sign:

1. Go into the sign of interest in Creator. 

2. Go to File>Export. 

3. Save your sign and this should download to your PC.

To import a sign:

1. Open Creator (select new sign but don't worry about the name as this will change when you import).

2. Go to File>Import.

3. Go to 'Choose file'. 

4. Select the file from your PC.