AWS Certificates Upload from nRF52

First, I have just started working with RAK5010 and second, I am not working with any API as I did not find any. I am using nordic SDK 14.2 and Segger Embedded Studio to develop the firmware as we already have ano board with nordic nRF52 chip. The problem is that we use AWS IoT and have to upload the certifications to BG96 from the nrf52840 programaticly. I know that it is possible and there is a document describing how to use AT commands for File manage. I have tried the folloing code:

Step 1) send: “AT+QFUPL=“privatekey.pem”,1702”
Step 2) received: CONNECT
Step 3) upload the file

On step 3 I have no idea about how to send the privatekey.pem file. Should I convert it to a char array, embbed it on the code and send byte by byte to the bg96?

Thank you all!