Have a potty book - something she wants to read that you only let her read on the potty.
Be patient. Be prepared for it go badly, then better, then worse, then better, then back to square one, then improve a bit, and so on & so forth for several months.
Tell her she is doing really well when she gets it right, but don't roll out the flags and blow the trumpets, or she'll suss how important it is to you or freak out with the pressure. Don't tell her off or punish her if she wets herself - it's as much about physical development of control as wanting to wee/poo at the right time/place.
Make it fun, e.g. buy pants with favourite characters on, or make up stories about poos who like to jump into the loo and go for a swim.
Find an old blanket to throw over your sofa.
Keep a perspective on it. Your DD is still relatively young. Very few kids are in nappies when they get to school age, so it will happen.