I need help knowing how to find an equation in standard form that fits the requirements.

major axis length 6 on y-axis, minor axis length 4

it is pretty easy.

major axis = 2a
minor axis= 2b

standard form:

x^2/a^2 + y^2/b^2 = 1

so in your case, 2a=6, a=3
2b=4, b=2