Substrate Developer Hub Tutorials
The Substrate Developer Hub has its own catalog of tutorials which will walk you through the various stages of writing and operating your own Blockchain based on the Substrate Framework. Most of them should be done in the order presented on the website. Also notice the estimated times it'll take you to work though such tutorials (based on your experience they might be slightly off, though).
The Substrate Recipes documentation acts as a cookbook for Substrate-based Blockchains. Whenever you have a hard problem to tackle, be sure to check the Substrate Recipes to see if it was already solved (and if so, how it was done).