Change all trails to Pet app

I want a app like (all trails) ui/ux but all trails is a hiking app, i want make this app more on pet app. And i want it can be uploaded at play store. And I want go map that i brg dog or cat go for walk the map that record time , current location, how many km we walk and how many calories we burn. And also in the trails that suggest which trails is pet friendly. I want to add another market site that can sell like pets food. How much will it cost?