If it’s ONLY the resistors and you magically know which ones: add solder to one of the pads, hold resistor with tweezers, melt solder with iron, push resistor into molten blob and position so it touches the second pad, remove heat so it’s frozen in place, then solder second pad.
If it’s ONLY the resistors and you magically know which ones: add solder to one of the pads, hold resistor with tweezers, melt solder with iron, push resistor into molten blob and position so it touches the second pad, remove heat so it’s frozen in place, then solder second pad.