The most simplest step to obtain sample of sodium chloride from seawater would be...
By the process of evaporation, take some volume of seawater in a container and place it over bunsen burner and let all the water to evaporate after evaporation the left over part will be impure salt. Generally sun heat is use for evaporation. This salt residue is mixture of all the salts, pure NaCl is obtained by industrial process.
To obtain samples of sugar crystals from sugar cane.
Juice is extracted from the cut peace of sugar cane
It is heated till the boiling point till it form thick brown syrup which causes the formation of crystals.
This mixture is further refined to remove molasses for this small amount of water is added to form magma. Magma under centrifugation will separate crystals and molasses which is further filtered to obtain sugar.
To recover sugar from sugar cane you would first break up the sugar cane stems so the sugar can be dissolved in warm water. Once the sugar has been dissolved the solids would be removed by filtration. The filtrate will contain the sugar dissolved in water. To remove color that may be present in the sugar solution you could do a second filtration through charcoal followed by treatment with a bleaching agent such as hydrogen peroxide.
The water is then separated from the sugar by evaporating the water, leaving behind solid sugar. The sugar can be dried and ground into the sugar crystals you buy in a store.
To remove salt from sea water requires the use of a large amount of energy. Normally the water is evaporated off, leaving the salt behind. To increase the purity of the salt, you would first filter the sea water to remove any suspended solids, then remove the water.