New house, first lawn

[home-hunting]

Hi there!

Looking for help to develop a year-round lawn care routine on our first lawn, knowing NOTHING about grass care.

We bought the house in early December after it had been finished in November, and before the contractors did anything with it, the land was basically a weedy/bushy lot.

We noticed in September or October that it had seed down, or at least what looked to me like seed - the kind of fluorescent mint colored stuff that definitely said, DON'T WALK ON ME.

We've had an incredibly mild winter this year (we're in Rhode Island), and I would say there have only been about 10 nights total where there was a deep frost, and only 2 full days where the yard has been covered in snow.

The grass is there, but is very thin, with what I would consider thin stalks. The ground seems to me to be sandy, and water collects in different parts of the yard after rain/snow melting - so maybe some drainage issues.

There doesn't seem to be many weeds in the back yard but the front yard has these weird thin branch type things that are coming up from the ground - they almost look like thin wires. I've been pulling them out and trying not to pull the ground out - pretty easy because of the sandy consistency.

What I'm looking to see is, what is a good routine for us to get on? No one was mowed the lawn ever, and we're not sure when the first time that should be. Since the grass is thinly covering the lawn (you can look down and see the individual grass strands, and a bunch of ground around it), do we reseed, fertilize, etc?

Looking for a schedule for mowing, fertilizing, seeding, using different products (I see farm stores selling all different things at different times of the year). Also, anything we can do about our soil short of digging it all up? Will we even notice once the grass comes in?

And lastly, I have access to a well composted horse manure/timothy-alfalfa hay/pine shavings/pine sawdust mix - does this work as well as commercial fertilizers?

Thanks for any help!!