If your spaghetti squash is not pre-cooked, cook as desired. Same goes for your ground turkey and lentils!
Add cooked turkey, pasta sauce, and cooked lentils to a fresh pan and heat together. If using shredded squash and not a roasted half, add this to the pan, too.
If using a pre-cooked squash half, warm in microwave. If it's freshly cooked, leave as is!