Publish a Unity Built Application to Both Play Stores

I need an experienced app publisher to help me publish and maintain an already built educational app to both the Google play store and the ios store.

The app was finished in 2017 but never released. It was built in unity to allow for cross platform development. It contains 12 modules. The first module is downloadable for free with the additional modules for sale either as an all in one purchase or in blocks of two modules each. The coding for the point of sale on the play store still needs to be completed so a background in Unity is essential.

To cut down on app size the assets for each module were split into various downloads that will install from our website www.literacymagic.com .I am interested in a fast publication but also in improving the downloading process. It would be preferable for all assets to be downloaded via the playstore instead of our website however this work can be split into multiple projects in order to streamline the process. The key issue is to publish the program as quickly as possible. Improvements can be made further down the road.