Create a Reddit Ads account if you haven't already, and navigate to the Conversion Pixel section in the Reddit Ads dashboard.
Generate a Reddit conversion pixel, which is a JavaScript code snippet, and place it on your website, preferably using a tag manager. This will allow Reddit to track user activity on your site.
Create custom audience segments on your website using your analytics platform or DMP (e.g., Adobe Audience Manager). This could be based on user behavior, content consumption, or any other criteria relevant to your marketing strategy.
For each audience segment, create a unique conversion event in the Reddit Ads dashboard. Assign a specific conversion event ID to each segment.
Modify the Reddit conversion pixel code on your website to fire the appropriate conversion event based on the user's segment membership. This can be done by conditionally triggering the pixel with the relevant conversion event ID using JavaScript or your tag manager.
In Reddit Ads, create ad campaigns targeting users who have triggered specific conversion events, effectively targeting your 1st-party audience segments.
Keep in mind that while this approach allows you to target your 1st-party audiences on Reddit, it may not be as precise as the built-in audience targeting available on platforms like Facebook or LinkedIn. Additionally, Reddit's advertising policies and guidelines may impose some limitations on the types of audience data you can use for targeting.