Let's make your life a bit easier, here's a guide on what creative assets you'll need for submission to the Google Play Store.
Google Play Store Copy:
A short description of your app to help engage your future community members and let them know about your app's key features.
The first 255 characters are immediately visible to users before they need to hit the "More" button. If you have information about pricing, this generally goes towards the end.
Google Play Store Video/Preview:
Offer users a preview to demonstrate the features, functionality and user interface of your app in a short video that can be uploaded directly from YouTube. You can add your preview or promotional video by entering the URL in the 'Promo Video' field.
Spec: you must use the full YouTube URL, not the shortened link, no longer than 2 minutes.
Google Play Store Screenshots:
Give your browsers a sneak peak of what to expect inside the app using screenshots of walls, media and other features.
You can either fill the app with content to easily take screenshots, or edit content into the screenshots.
Spec: JPEG images, 1242 x 2208 pixels, recommended 3-6 screenshots
You will also need to provide a banner image for the top of the phone's interface, as well as a logo. The banner could be of a relevant stock image, or your app's logo. This will show in the preview when the app store link is copy and pasted somewhere.
Spec for square icon: JPEG image, 512 x 512 pixels
Spec for banner image: 1024 x 500 pixels
Here are some useful tools to help you best create these: