Create a Google Ads campaign via the API (budget, campaign, ad group)

Steps

1. Authenticate with OAuth 2.0 and prepare your developer token and customer ID.
2. Create a CampaignBudget resource by calling CampaignBudgetService.mutate with a desired amount_micros and delivery method; capture the returned resource name.
3. Create a Campaign resource via CampaignService.mutate, referencing the budget resource name and setting advertising_channel_type, status, and bidding strategy.
4. Create an AdGroup resource via AdGroupService.mutate, linking it to the campaign resource name and setting a default CPC bid or target bid.
5. Optionally batch all three mutate operations into a single GoogleAdsService.mutate call using temporary resource name references (e.g. customers/CUSTOMER_ID/campaigns/-1) to reduce round trips.
6. Verify creation by running a GAQL query against the campaign and ad_group resources to confirm status and budget linkage.