Hiroshi 开始创建广告素材。他应采取哪些步骤？请选择所有合适选项。

When creating ad creatives, Hiroshi should follow all the listed steps. "Collecting ad content" is the initial planning phase, where he gathers text, images, and videos. "Uploading new multimedia content" is necessary to bring those assets into the ad platform. "Filling in details" involves inputting the ad copy, headlines, calls to action, and destination URLs. Finally, "previewing the ad" is crucial to ensure everything looks correct and functions as intended before launching the campaign. All these steps are integral to a successful ad creative development process.