About replacing "Makefile" with "Segger Embedded Studio"

Hi,

Normally the most efficient way to do this is to start of with a SES example project from the SDK that matches as close as possible what you want to do (Same IC, same SoftDevice, etc). Then manually add the files you need, and adjust configurations. This might take a bit of time, but that is how it is.

I understand how to do that.
However, I don't know if the method is correct because of the error.
Is there any material that shows the procedure?

I understand how to do that.
However, I don't know if the method is correct because of the error.
Is there any material that shows the procedure?

The "multiple definition" error is because you have includes two files that implement the same function, in this case Reset_Handler(). This is implemented in the startup file so it probably indicates that you by a mistake have implemented two startup files. One ifs from the MDK (which is correct and expected), and the other I cannot see from this screenshot. But you should search your project for Reset_Handler() and then you should find it.

The startup file was duplicated in GCC and SES.
Compiling was successful by deleting the GCC startup file.
Thank you for answering.