Hello,
There were two plans while creating the new constitution: The Virginia Plan and The New Jersey Plan.
The Virginia Plan is the plan saying that the amount of representatives and senates in the legislative would be based on population. This gave advantage to the bigger states, because the bigger state would have more people representing their state.
The New Jersey Plan is the plan saying that everything should be kept the same in the legislature, every state has the same amount of representatives and senates in the legislature. They thought The Virginia Plan was not being fair to the smaller states, because the smaller states would get little representatives to represent their state.
In conclusion, The Virginia Plan is the plan that the representation in the legislative should be based on population.
Hope this helps!
May