Fail to initialize variables

Hello friends,

I created a theme with features like customizable social links and banners. Created a theme option page for user to manage these items.
They all work perfectly fine with just one problem.

When a user installs my theme then there custom options are not initialized unless the user opens the option page and save changes.

When I looked into the problem i saw that when the theme is installed at that time it has no entries in database for my custom variables. It does that when a user clicks the changes in the theme option page.
Since the theme is based on conditions such as “if banner = enable { show banner … ” therefore these conditions can not work if they can not find there values in database.

Friends kindly guide me how to enter my custom values & there STD at the time the theme is installed.

Thanks 🙂