Just make sure that you plug the floppy connectors in the right way up. Make a note of the way they come out. There is a right way and a wrong way and it is possible to connect the wrong way if you are not careful.
The DC power connections of an AT PSU to the mother board is two in-line connectors, P8 & P9 (which can be connected in reverse if you're not careful.) An ATX connector is a keyed single 2-row 20-pin connector with a retaining clip on one side.