A. The foundation of the triangle is your website + blog. The website says who you are and what you do. The Blog provides fresh content to be shared with your audience and Google food.
B. Social Media Marketing - you can take pieces of your blog posts and make short posts with branded memes. Create content once, use again & again. You can use social media to entice people to sign up to receive your newsletter. Get leads.
C. Email Marketing - You can share your recent blog posts, by excerpting from it and linking to it. You can inform your readers that you have a private Facebook group or you go live on Fridays. Build a following with your mailing list, and direct them to your social media. Your social media can promote your blog & website, and on and on it goes.