Hello,
You have to follow these steps to create the solution of InfoPath,
1. In Visual Studio, File -> New -> Project.
2. You have to choose language in left side of Project types in New Project window.
3. Select Visual C# to expand and select Office then you can see ‘InfoPath Form Template' in right side Templates.
4. Click on OK button.
5. In ‘Design a Form Template' window select ‘Blank' and click on OK button.
You have InfoPath form with solution. In this form you can add your controls and double click on button and choose Edit Form code to enter the code file.