Cross a plant that is heterozygous for green pods with a plant that has yellow pods

G=Green ... because your starting plant is heterozygous it must be Gg

g = yellow ... because yellow is recessive, it must be gg

Gg x gg

Do a Punnet Square and you get

Gg (2)

gg (2)

So half of your plants will be green (but heterozygous) and half will be yellow (homozygous)