100% front end / 50% backend means you'd need a front-end product (meaning, your book) but followed by an upsell for those bought your book (that's the 'back-end").

That model is likely the simplest funnel and a great baseline to start from.

Trying to sell just one product (front end) is often a lost cause.

Adding on an upsell makes it a degree more attractive for affiliates and gives you an additional opportunity to buy paid ads and not lose your shirt on it.