Before jumping into making a game, you should do a bit of research and maybe a couple of tutorials. The research part is looking at what engines are available and which will fit your needs and skill set. I can only speak to the ones I’ve used: Unreal, Unity and Phaser. In the order I listed, Unreal is the most difficult to learn but does more of the work for you. Phaser is the easiest to learn, but you will be hand coding EVERYTHING! And Unity is somewhere in between.

As far as coding, Phaser uses javascript and you will code everything. Unity uses C#, but you’ll mostly be attaching individual scripts to objects. And Unreal uses C++, but, most likely, you won’t write a single line of code.

Myself: I use Phaser because it’s what I use at work. I’m writing code in Phaser for 8+ hours a day - so I know my way around it. This is part of choosing an engine. Unreal or Unity may be a better choice for a given project, but I personally could get the project done in Phaser in less time.

As for your question of art vs coding: TBH, most people focus on one or the other. The reason I have an account on this site to begin with is I’d rather just buy some artwork that’s already done and dive into the coding.

Leave the final art until later.  The reason is that you probably don't know exactly what art you need at the beginning.  If you buy or create art before prototyping the game, you are likely to find that some of it doesn't meet your needs and has to be redone or replaced.  It's generally best to start with placeholder art and fill in the real art as you go.  A five-second scribble or grey box works just fine at an early stage.

As for how to get started, if you don't have a programming background, I would probably just pick a free engine like Unity or Godot and start doing the tutorials.  They start out very basic.  What technologies work best for a given project just depends on the nature of the project and your personal preferences.  I would really recommend doing some small projects first to get used to the process, decide if you like the tools you are using, and get some rookie mistakes out of the way.  If you are starting from scratch and try to jump straight into a large and complex project, you will probably have a difficult time.

Midnight Spire and Pritt have some great advice, especially in regards to tutorials. 

To add to that, I would recommend getting your basic game loop working before spending too much time with levels and assets. By "game loop" I mean all the logic from starting the game, playing a level and then failing or continuing to the next level, quit and restart options, etc. If you anticipate that your game will have a menu of some sort, do a very basic text-based menu first with only the most essential features (Start, Save, Load, Quit, etc).

Think of the "game loop" as the skeleton of the game.