I have develop one app which is known as project management app I am trying to integrate with teams, like whenever we download file it should be showing in file tab of application in teams, plus whatever we create new post it should integrate in teams calendar.
same thing with files--each team channel has its own files, so depending on what channel your app is in, you will need to store the files in the right location for them to show in the correct files tab.. Go to the files tab in which you want the files to appear, click the open in SharePoint link, and copy the URL of the document library that is used by the desired teams channel.
Also, since you are doing project management, you may want to also incorporate Planner for your project tasks. There is a great connector for planner, but there again your team could be connected to any planner environment/project, so you will need to specify in your app with planner to use to create tasks.
To summarize--teams is a great experience in that it brings together multiple disconnected pieces into a cohesive whole experience; however, there is no way to dynamically get the calendar, files location, and planner environment that are connected to the Teams channel in which your app is embedded. You will need to specify those locations when you build your app.
@sagar_shah if this answers your question, please mark it as a solution.