Beginner Gardening: New homeowner lawn questions, 0 by CRBVA

CRBVA wrote:
Hello!

I recently bought a house in Virginia and as we're just now coming out of our first winter I'd like to finish getting the back yard grass to grow. Originally when we settled there was no grass whatsoever and the builders put down grass seed and straw. Parts of the lawn has grown robustly, other parts have large bald spots. There are also parts where the ground has collapsed and eroded away (pictures 1 and 2).

Regarding the erosion: Would filling it with topsoil and planting grass be sufficient to prevent further damage? It is my hope that a root structure would keep everything together, but I know next to nothing about landscaping or lawn care in general and would like to know if something more would be needed.

To plant grass seeds, what should I do to help it along? Should I get more hay to put over it? Turn up the soil before sowing them? Should I water them periodically? There are parts where it is pretty rocky (picture 3). Do I need to remove the rocks or will they not matter?

It also looks like when building the house that materials were brought up by truck from the rear of the property. It looks like sand was put down to help with traction (picture 4). Would I need a different type of seed for sandy soil? Would I be better off putting down topsoil over it before planting?

I apologize for having so many questions, but I'd like to try and do this right. I'd appreciate any thoughts or comments that could be offered. Thanks!