I have grow lights now but I started tomatoes and peppers in sunny, south-facing windows for years with good results.
You’ll want to up-pot pellets once the second or third set of leaves start to show. I use red solo cups filled with a homemade mix of potting material. I use an ice pick and poke several small holes in the bottoms for drainage. I grow them out there until they are ready to go into the ground or container. You can reuse those cups many times. I’ll use a sharpie and trim tape to label them if needed.