How do you separate a solid and liqui that forms a solution?

It depends on the solid and the liquid used. For instance, sand and water may look cloudy when stirred together, but the sand is not dissolved into the water, it is not a solution, and the sand grains will simply settles to the bottom.

Taking salt and water, as an example. It is possible to dissolve salt crystals with water to form a clear (transparent) saline solution. To separate the salt from the water, you use heat to evaporate the water into a vapour (steam) leaving the salt crystals behind. If the water vapour is then condensed back into water, you are left with salt and water, both separated from each other.