Well if u want more gentle introduction to newest version of dots(0.50, 0.51) u have Turbos tutorial and Moetsi also did an excellent job : https://dots-tutorial.moetsi.com/ , i must admit i did not make it clear enough that last two on my list cover more 0.17 version or previous ones(which have support for animations for example), DevViktoria on the other hand has more advanced dots tutorial - she also has 0.50 related videos. Also dots is constantly evolving tech so u can expect breaking changes when for example 1.0 is released…
Spawning entities, using prefabs(prefabs are GameObjects turned to assets u can instantiate at the runtime very cool classic Unity feature - spawning prefabs is absolutely basic thing u should learn first in dots) etc is explained here :
https://docs.unity3d.com/Packages/com.unity.entities@0.51/manual/conversion.html#prefabs
a bit more advanced tutorial(or list of all options u have in dots) on spawning prefabs is here :
I really recommend u Moetsi tutorial if u want to learn dots gradually from the basic things also u have link on his site to his discord server where u can ask for explanations - there is friendly community which will help also u have Unity discord server with dots related channel and also here on this forum u have plenty of threads with explanations of basic things u are searching for(there is Turbo’s discord server too) …