Advertising on Apple Podcasts is not directly done through Apple. Instead, you will need to work with podcast creators or podcast advertising networks. Here's a step-by-step guide on how you can advertise:

1. Identify Your Target Audience: Before you start advertising, it's important to know who your target audience is. This will help you choose the right podcasts to advertise on.

2. Find Relevant Podcasts: Once you know your target audience, look for podcasts that align with your brand and have a similar audience. You can use Apple Podcasts to search for podcasts by category or use podcast databases.

3. Contact Podcast Hosts or Advertising Networks: Once you've found the right podcasts, the next step is to reach out to them. Some podcast hosts manage their own advertising, while others work with podcast advertising networks. You can usually find contact information in the podcast description or on the podcast's website.

4. Negotiate Rates and Ad Formats: Podcast ads can be pre-roll (before the episode starts), mid-roll (in the middle of the episode), or post-roll (at the end of the episode). Rates can vary depending on the podcast's audience size and ad format.

5. Create Your Ad: Podcast ads are typically read by the host, so you'll need to provide a script. Make sure your ad is engaging and clearly communicates your message.

6. Monitor Your Ad's Performance: After your ad is live, it's important to track its performance. This can help you adjust your strategy and get the most out of your advertising budget.

Remember, podcast advertising can be a great way to reach a highly engaged audience. However, it's important to choose the right podcasts and create compelling ads to ensure your advertising efforts are successful.