Update step_by_step.md

Author: iwatkot

docs/step_by_step.md

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 ## Create a Farming Simulator map in 10 steps
 
+📹 A complete step-by-step video tutorial is on [YouTube](https://www.youtube.com/watch?v=Nl_aqXJ5nAk&)!  
+
 Hey, farmer!  
 So, you're ready to create your own map for the Farming Simulator? Great, the `maps4fs` tool will save you a lot of time and effort. In this section, I'll guide you through the process of creating a map from scratch using the generator.  
 This tutorial will contain a short description of each step, but you'll find detailed tutorials in the [docs](https://github.com/iwatkot/maps4fs/tree/main/docs) directory of the project.  
@@ -8,7 +10,6 @@ Just in case: remember to check the [FAQ](https://github.com/iwatkot/maps4fs/blo
 
 Let's roll!
 
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 ### 1. 📍 Get the coordinates of the center of your map
 It should be easy to do with [Google Maps](https://www.google.com/maps) or [OpenStreetMap](https://www.openstreetmap.org). The coordinates are latitude and longitude values, for example, `51.5074, -0.1278` for London.  
 ℹ️ This point will be the center of your map, not the top, not the bottom, but the center.