If you are having issues with how the App itself behaves, if it won't do something you expect it to do, like show your instances, or let you browse available packs then you'll want to find your App logs. The process of doing this is really simple, you just need to go into the settings menu then find the upload logs button. Once you click that it will automatically upload your log and copy a url to your clipboard that you can share with the person that is trying to help.
How do I find my App logs?
If you have been asked to provide your logs for troubleshooting purposes this will explain how to find them and how to get a link to them. There are 2 sets of logs that are useful for trying to find out what has gone wrong, which logs you need will depend on how far into the launch process you managed to get before your crash/issue.