understanding array - (Oct/23/2019 )

Hi, Im trying to understand how arrays work and would be grateful for feedback. Apolgies if its a naive question.

an array would have single strands of cDNA on a chip. The sample that is to be tested (cDNA) also has to be in single strands right or how can double helix DNA bind  to the single strands of cDNA on the chip? 

you are correct, you want single strands. therefore, you denature your dna if you start with genomic dna.