What like, you want class design? Ok sure.
Fundamentally, the Ranger is a lightly armored skirmisher class. The design, therefore, slots neatly between Barbarian and Rogue. d10 Hit die, proficiency in Light and Medium Armor, no shields, but perhaps an Unarmored Defense ability that kicks in at higher levels (much like how a Barbarian wears armor early in his career, but can dispense with it later). The Ranger would get increased movement speed, and eventually bonus action Disengage, to benefit a "hit and run" style of combat, should the player wish to engage in such.
The Ranger would then get a selection of Terrain Types as they level up. When in a Terrain they have trained to fight in, they get bonuses to Perception, Survival, and Stealth. These need not be numerical bonuses- I would prefer expansions on the abilities: for example, they might gain a Camouflage ability, allowing them to Hide in plain sight while in that terrain.
The Ranger would gain an Ambush ability, allowing them to either snipe or perform a takedown of an opponent they either surprise or attack from a hidden position. Thus the base Ranger's fighting style consists of finding a place to hide, jumping someone, then quickly retreating to a new position they can hide in. This isn't as reliable as Sneak Attack, simply because they are a tougher class in melee.
Then the three subclasses bolt onto this. Magic Ranger allows the Ranger access to spells, with a few choices of "Magic Tricks" as they level up, allowing them to diversify their abilities- perhaps they go into Magic Trap Spells, or pick up something like the Smite series.
The "Martial Ranger" grants the various fighting styles we know and love, supporting dual wielding, ranged combat, and so on, as well as specialized abilities to fight monsters- similar to the Hunter subclass.
And finally, the Beastmaster allows the Ranger to acquire animal allies, and work in tandem with them to better harry and defeat foes.
