My go-to site is ‘The Old Farmers’ Almanac.’ Amazingly detailed information to be found there.
https://www.almanac.com/gardening/planting-calendar
For beginners I always suggest a gardening book specific to your Growing Zone. You can also find out what that is at The Almanac.
And, I also like the ‘Square Foot Gardening’ book. Look for the most current printing - it’s been updated a number of times. Lots of charts and such as to when to start seeds inside, or when to direct seed, how to make the most use of your space, crop rotation, and planting succession crops to keep things going well into the Fall.
Looks like the FOURTH edition is the newest edition, and will be available December 2024. (Per Amazon)
In the past there have also been recommendations for Johnny’s Seed catalog/site for planting guides and timing, etc.
https://www.johnnyseeds.com/growers-library/online-tools-calculators.html
One of the things I want to do for next year is build a couple cold frames just to try and see how much of a start I can get on cool weather crops.