Yes, that's the process.
However, there is another recommended step if you want to update your style later - after installing that style, create a new child style. Import style XML file, then click "Create New Style" button, select style you have just imported as parent style and submit form.
What do you need that for? To keep your customizations when updating style. When in future you will be updating style, you will need to import new XML file, which will overwrite all templates and style properties. That means your custom changes will be lost. However style import does not affect properties customized in child styles. So instead of applying your changes to downloaded style, apply changes to child style.
For example, you have downloaded and installed "Awesome Style". Create new child style "My Style", then set "My Style" as default style. Then in styles list uncheck box for "Awesome Style" to make sure users can't select it.
When you'd want to change something, like logo path or anything else, edit style property in "My Style".