Facebook advertising is an art and a science...to be honest, to some extent it is a black art, that you learn from the FB gurus camped deep in the mountains conducting their strange rites and invoking the blessings of the pantheon of deities amongst whom rule chiefly Zuck the hooded one and the mysterious Facebook AI wizards.
This is not an area of inquiry to be approached lightly. The non-believers think there is nothing here, they couldn't be more wrong. Those who have played with the fire and been burned are afraid to tread here again, this is understandable.
I would suggest you seek out someone who has walked through the fire that is FB ads and survived, one who has at least managed to turn some lead into gold.
Don't trust mainstream advice much. Understand the difference between brand and direct response marketing. Think in terms of a complete marketing funnel including social media presence, email marketing, re-marketing, customer lifetime value. Be metric driven from the first moment. You need to split-test and optimize continuously, this is not a child's game. The basic sequence is probably: ad --> landing page --> main page with call to action --> regular email follow-ups and re-marketing as needed. Bonus points for creating specially tailored campaigns to each of your target groups.