Log in to your account. 2. Create a duplicate of the campaign you want to test in an A/B test. 3. Click "Drafts & Experiments" → "Campaign Experiments" → + button. 4. Select your duplicate, name the experiment, and choose a start date. 5. Set the advertising budget. Choose the percentage of the campaign budget participating in the experiment, for example, 50%. 6. Save your experiment and wait for the results. That's it. Google Ads has its own calculator that does all the calculations and shows which variant won.