How to build in C++ inside QT?

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C++

QT

QT-Creator

I am new to using QT and this is my first project inside QT. I built this project in QMake within C++. I don't know QT. But I want to learn it. I want to create a build of the project which can't be done by me. It is like a problem that I don't understand. Please help me create a build. Thank you!

What I have tried:

I build like this:
-> I open QT.
-> On the left, at the bottom, there is an icon like a computer, from there I select "Desktop QT.5.12.2 MinGW 64-bit" and select "Release".
-> Then I run the project. So there is a folder in the path where my project is located and inside that folder is a folder called "Release" and inside that folder, an EXE is created.
-> But that EXE doesn't run. After adding all the DLLs to the folder containing the EXE, I get this exception.

Exception:

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QT_Camera.exe - Application Error
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The application was unable to start correctly (0xc000007b). Click OK to close the application.
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exactly
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