In any case, check out the topic about design principles in our early validation course. You might find it useful to study design before beginning to build your social media posts.
Before you start posting, you want to create a social media plan. Our course on content marketing guides you from strategy to plan to execution.
The best templates for social media posts can be found on Canva. By clicking on this link, you will be directly guided to a variety of social media posts suitable for Facebook. Pick one that fits to your style.