Changing a campaign that is already running. Budget, bid, dates, targeting and creatives can all be adjusted after launch, which is how most growth teams at exchanges and iGaming brands actually work.

Open Advertising > Campaigns.
Open the campaign you want to change.
Move to the step holding the setting: Settings for the landing page, name, dates, budget and bid; Targeting for segments and geo; Creatives for the assets.
Make the change and save.

What to change, and what to leave

Change one thing at a time. Moving budget and bid together leaves you unable to say which one worked.

Give each change time. Delivery responds over hours, and the algorithm needs volume before its numbers mean anything.

Widening targeting is usually the fix for slow delivery, more often than raising the bid. The estimates panel in Targeting shows whether the audience is large enough to spend the budget against.

Editing creatives sends them back to review, so a live campaign pauses on that creative until the review completes.