GMS 2.3+ Mixing DnD & GML?

Sorry for the noob question and if you've already answered it before too.

Can you mix DnD programming with GML?

I mean if it is possible to write some GML code, but then use some DnD to save time with some process, and then go back to GML?

Or if I start with DnD, I can only use DnD (and the same for GML).

I ask this because I am doing all the DnD tutorials and then I plan to do the GML ones.
But I'm afraid that what I learned in DnD won't help me later if I learn GML later.

Thank you!
Thank you very much @TailBit & @TsukaYuriko for your answers! piuffff! now I'll try to learn DnD the best I can, and then, I'll begin to learn GML and mixing it with DnD till... someday very far away, I can write all the stuff in GML :)