Like any backyard sports skill you learn at home and practice to improve you then transfer those same familiar skills to the playing field or court.
To build the basic swimming skills at home I show you how to use a kitchen sink, dressing mirror, mattress, and a bathtub. Then you transfer those same familiar skills to the shallow end of a pool or lake where you can stand up.
To stand up you simply hold your breath, and bring your knees up strongly to your shoulders to rotate your bottom down as if to sit in a chair. Then wait until you see and feel your feet firmly planted on the floor of the pool or lake, and slowly stand up.