What is this 5' and3' what they do implies. Better if you tell whole description about structure of pollinucleotide chain.

5’ implies the Phosphate attached to 5^thcarbon of Deoxyribose sugar. The 3’ implies the OH which is at the 3^rdcarbon of the sugar.

Polynucleotide chain of DNA is made of many nucleotides. Each nucleotide has 3 components: 1. Nitrogenous base( adenine, Guanine and Thymine and cytosine)
2. Deoxyribose sugar
3. Phosphate group which is attached to 5^thcarbon of the sugar.

Both the DNA strand are polynucleotide which are forming a helical structure. The nitrogenous base on one strand forms Hydrogen bond with nitrogenous base of other strand.
See in the image