I assume by "being an introvert" you mean you have social anxiety. If so, start out by looking for things you need online, followed by your location. Many local businesses will have some kind of online presence, or at least a Facebook page. Check what businesses those pages follow or interact with. At least that way you'll gain some background.
Buying local is ideally going to be a more social experience. You will start having to seek out local markets and meeting the people who provide their goods and services. You'll also find it easier once you visit local places For example, the local brewery here hosts markets. Local supermarkets buy food from (relatively large) local farms. Smaller local farms work directly with local restaurants. It's all interconnected.