Dùng tay đẩy cơ thể nổi lên.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in Chinese about that?
如果你在水下，想要浮出水面，用双手将自己向上推进。将它们伸直过头顶，然后迅速向下划到身体两边。这样一次能让你向上移动一米多，重复动作直到浮出水面。