Ah I see…
First the simpler bits. Adding the icon to the application is done in App Wrapper, on the the first page within App Wrapper, there is a Icon field. Either drag in a Retina compatible (it doesn’t matter if your application is not Retina ready, you still need a Retina compatible icon file) icon file or a transparent image that is at least 1024 x 1024 in dimensions.
As for installing the application, when you submit to the Mac App Store, App Wrapper can make an OS X Installer Package for you (which will automatically install the app in the apps folder). If you sell via your own site or others, you can just use a zip file. Many Mac users are accustomed to simply moving it to the Applications folder, I wrote some code several years ago called “Install Easy” it’s not compatible with Sandboxed applications but it can ask the user if they want to move the application into the apps folder.
The Mac App Store; this is going to be the hardest.
You’ll need to make modifications to your application, for instance your application will need to be Sandboxed, which will prevent your application from writing to the users documents folder unless they explicitly choose to save the document there. Unless the user chooses, your app can’t even create an empty folder there.
App Wrapper will help you with the configuration of your application and the post production functions required to submit to Apple, such as adding plist entries, code signing and making the installer.
You are however going to have to sit down and read the following document. Mac App Store Review Guidelines
It’s a list of reasons that Apple can reject your application (there are others not listed). Basically when you submit your application to Apple, they’ll review it and either approve it or reject it.
I’ve been shipping apps on the Mac App Store since it’s inception and I still fall foul of these guidelines. Don’t expect Apple’s review team to help you when they find what they think is a reason for rejection either. Only a couple of times have we ever received clear and concise information, most of the time the reviewers just quote the guidelines and give a scant one liner, writing to them and asking for help… It’s easier to get blood from a stone.
I love the Mac App Store in terms of what it’s done for my small business, but getting an app on to the Mac App Store has become the hardest part of software development. However if you’re not on the Mac App Store, you’re missing out on millions of customers.