We published a checklist to our blog that guides you through what you need to do:
https://coronalabs.com/blog/2018/05/16/getting-your-corona-apps-ready-for-gdpr/
But to summarize here.
You, the developer present a dialog box of your own design that fits the style of your app that:
a. Tells the user that your app is going to be collecting data.
b. Provide a link to your privacy policy on your website.
c. In that privacy policy, provide more context that your ad providers are collecting data and link to their privacy policy.
d. Provide a UI that ask them to either consent to this, or decline it. It could be something as simple as a checkbox, on/off switch etc. using widget.newSwitch. This should be defaulted to no consent, since the EU’s intent is for the user to actively opt-in and not opt-out of consent.
e. Save that setting with your other app settings.
f. On your settings screen, provide the user an option to change their mind.
g. Decide how your app will behave if the user does not consent.
h. If your ad plugin will provide non-targeted/non-tracked ads, you can then pass the consent choice to the ad plugin according to the documentation for that plugin. If your plugin doesn’t have a consent API, then simply don’t initialize the plugin if there is no consent.
Rob