What is the sequence of commands for downloading a program via JTAG?

Question

JTAG

I understand with FPGA, and I feel that sooner or later there will be a need to understand the JTAG interface. All the descriptions that I found on the Internet are limited to information about the pins, the xilinx documentation mentions some of the boundary-scan commands of the register, but it’s still not clear at what settings and what TAP commands the controller perceives the bits as a program for the FPGA and not just testing the pins. An example of the following type is of interest: the leg is pressed to a certain level, the command is sent "right now the program for the FPGA will go", the program itself goes and takes up space in memory, the end. Are there similar examples somewhere?