If you open your own Character Skeletel mesh and switch to the animation screen your animation asset browser is most likely empty (if not you are not missing animations, you are missing an animation blueprint, that is another story). If you dont have animation you can load the animation starter pack from epic into your project and retarget these animations to your own skeletal mesh folowing this tutorial.
curiously if you do so, you can retarget all starter pack animations but not the standard once idle walk and run (even thou they share the same rig). But you can export these as fbx and import them to the starter pack skeletal mesh which will automatically create a animation sequenz that you can retarget. Once you have animations on your own skeletal mesh you can follow epics video tutorial series about animation blueprints/blend spaces etc. to actually use your animations in game.