Learn how to a block that turns into an entity when ignited or powered by redstone, the entity will then explode after a delay.
The best way I have found to make TNT in MCreator is to make a basic block than have it turn into an entity, this way it can act like vanilla primed TNT and be used in TNT cannons and have gravity. The only downside to this is it can't flash due to limitations with entity textures.
The latest download has all the files used in the tutorial video.
Questions and Help
If you have any questions ask on my discord server under the #mcreator-help channel so others may be able to help if I am busy.
Some procedures require local variables added before you import the procedure, all local variables need to be local number variables