Once you are happy with your Style Collection having applied the formatting required for each Style you can save it as a template for future use.
Saving a Style Collection
You can save the style from the Style Designer window.
Click on Style Designer.
Then, click on Actions dropdown.
After that click the Save As button.
A new window will open where you can choose where to save the template.
Next, give the Style a name.
Using a Style Collection
Now that you have saved your template it's time to use it.
Open the template to which you want to upload the style to.
Go to Style Designer.
Click on Actions.
Then click Open.
Finally, find where you saved your template and select it.
Once a style collection is applied to a template it will change all elements within the template to those styles. Remember to save the template.