Honestly, you can google "how to cook spaghetti squash" and get videos and a ton of instruction, but I'm all for keeping things easy and making it realistic, so here's what I do:
Preheat oven to 350 or 375 degrees (dependent on what else I have going into the oven)
Pierce spaghetti squash
Place on a baking sheet (I line it with foil or parchment for easy cleanup)
Bake approximately 30-40 minutes depending on size. Smaller squash will cook more quickly than larger squash. Check the squash after 30 minutes to gauge cooking. The squash is done when tender: The squash is ready when you can easily pierce a fork through the flesh all the way to the peel.
Allow it to slightly cool for comfort of touch, slice in half, remove seeds, and use a fork to "scrape and pull" (see picture) at the squash. The flesh will separate easily into spaghetti-like strands.
As per my usual M-O, i do not hesitate to use 1/2 of it and put the other half in the freezer for a later date!
Spaghetti squash has a mild flavor. It's not something you'd necessarily serve all on its own, but it's fantastic when paired with sauces and other richly seasoned main dishes. I use it in place of pasta with my favorite red sauce, and typically throw in other vegetables, like zucchini, spinach, fresh tomatoes, herbs, etc. I also love it layered in casseroles. I even throw it into curries or use it as a base in stir fries! If I'm serving the squash as a side dish, I usually toss the noodles with a little butter or olive oil to keep them from sticking, and season them with a little salt and fresh herbs. A sprinkle of nutritional yeast on any of the above adds extra nutrients and a bit of that "cheesy" flavor.