Sink your heels,engage your core roll your shoulders to give your back a more straightness and try sitting on your "seat bones".
Yes flex your stomach while leaning forward. But don’t forget to breathe!
Also lots of core and leg exercises in the gym helps!
It helps you to keep stable and balanced
Try to think remind yourself to “tighten your stomach muscles” don’t quite know how to formulate myself since im swedish but yea 😂