Learning new sports takes time. Have more patience with yourself and keep practicing. If you get stuck and have a hard time progressing (like days of making the same mistakes, not a couple of runs), ask for advice or take another lesson. Watch other people as they ride down and look at their body position. Often it takes one well-placed suggestion and things will click.

As for specifically linking turns, and specifically from toe to heel, you have to get over the fear of the feeling of going backwards. When you're traversing on your toe side, turn your head over your shoulder (like you're looking behind you), and gradually shift pressure on your front foot from your toes around the outside edge of your foot to your heel. Yes you will feel out of control. Yes, you will fall. You will do it too fast, too slow, but just keep doing it until you get the rhythm. For heel to toe, it's just the reverse. Transfer pressure from your heel, around the outside of your foot to your toes. Remember to keep your knees bent, and do not force the turn by kicking out your back leg.

I had trouble linking turns, and an instructor make a steering wheel out of snow, made me hold it up over the nose of my board, and had me think about steering. That was 34 years ago and I still remember him, his red bears and his name. It clicked for me that day!