I have some traits which were scored on bi parental population. I would like to estimate narrow sense heritability. I estimated the broad sense heritability
I recommend that you read chapter 4 of Hallauer, Miranda-Filho, and Carena "Quantitative Genetics in Maize Breeding". You will find all your answers there.
There is a full-text of the latest edition of this classic text available on the internet, but I will not link to it as I am uncertain of its legality.