Sinking legs advice for a beginner?

Guys,

Thank you so much for taking the time to respond to my question. I appreciate all your suggestions and I will take into consideration all your advices.
Generally, I’m a person who doesn’t give up easily and I think I will overcome this issue gradually as time goes by. I will swim 5 times a week and I will integrate all drills mentioned above.
I believe that the important thing here is to stay as much as possible in the water so you can get your body to flow naturally without thinking that your legs will sink any moment and a LOT of practice.
I will work on my core and glutes simultaneosly so I can minimize the drag in the water.
I totally agree with the statement of one respected member who mentioned that kicking is overrated.Hence, I would like very much to learn to swim like an actual triathlete without using my legs. I’m aware that this will be a daunting task, but its totally worth trying.

Thanks a lot!