Hi @pyi285
take a look at the original sample projects of bootloader+application. The linker files show what the layout is.
In case of MPC5674F, I would consider layout like this:

Of course, it depends on your needs. If you do not need Emulated EEPROM or data storage in those 16KB blocks, you can move the bootloader directly to the beginning of the flash.
Important point is that the bootloader/application should be always aligned to partition to avoid read-while-write issues during programming. In suggested layout above the bootloader occupies whole partition 3. Another option is to use only four 16KB blocks for data, so the bootloader can be forced either to partition 1 or 2.
So, layout planning based on your needs should be the first step here.
Regards,
Lukas