Thanks for reaching out about this.
If you aren't comfortable with coding, the easiest way to include add to cart buttons onto your collection and homepages is by installing a third-party app. There are a few apps on our Shopify App store that can help you achieve this, but I did find a couple that you might be interested in. Feel free to take a closer look at them:
Just a note that these apps are made by third-party developers outside of Shopify. So if you need more information about each respective app’s functionality, I recommend getting in touch with the app developers as they are best equipped to answer app specific queries.
It's such a great idea to include add to cart buttons onto your collection and homepages. It'll definitely make it easier for customers to purchase your products, and hopefully that will help increase your store's sales too! It sounds like this is an aspect of your store that you're focusing on at the moment, so I thought I'd include our Shopify Blog here on increasing your conversion and sales rates. The blog includes a few tips and tricks on the different strategies you can look into to optimize conversion and sales rates, including the use of analytics, and thinking of your homepage as a physical storefront. I highly recommend looking into the blog if you haven't already done so.
Let me know how you get on with the information above! I'd be happy to help if you have any other questions.