We've already covered how to redeem the Ardennes War Horse pre-order bonus, but if you indulged in one of Red Dead Redemption 2's many special editions, there is other content for you to obtain too.
You can redeem these bonuses at any time, but they are a great help at the start of the game so we suggest doing it as soon as you can.
Physical Activation Code/ Digital Download
The extra content is all packaged into a single DLC activation code, supplied with your copy of whichever edition you bought. You'll need to redeem install it alongside the game on your console. This can be done the same way as activating any digital content on the platform, through the console's OS, not in-game. If you bought the game digitally, there is no need to do this step.
Once that is complete, the bonuses are "in" Red Dead Redemption 2, you just need to find them. The easiest items to come by are the Nuevo Paraiso Gunslinger Outfit - a nod to a city in the Mexican portion of the Red Dead Redemption map - and the Eagle Talon Talisman.
Nuevo Paraiso Gunslinger Outfit & Eagle Talon Talisman
Upon reaching Chapter 2 in the story, the camp becomes accessible to the player. Here, at the foot of Arthur Morgan's bed is a chest that acts as your wardrobe, allowing you to edit and customize your outfit. Both the Nuevo Paraiso Gunslinger clothes and the Eagle Talon Talisman should be unlocked and ready to be equipped.
The outfit is comprised of several independent pieces of clothing and accessories, all of which you need to toggle individually. This might be a bit of a hassle at first, but such is the price of extensive customization. The Talisman's effect increases Eagle-Eye duration by 5 seconds.
Dappled Black Thoroughbred Racehorse
The Thoroughbred horse can be unlocked at any stable you visit from Chapter 2 onwards. During one of the missions in Chapter 2, Exit Pursued By A Bruised Ego, you need to visit a stable anyway, but if you're past that point the horse will be there in all stables in the game. If you pre-ordered the game you will see your War Horse can be obtained there too.
Volcanic Pistol, Varmint Rifle & Pump Action Shotgun
You also unlock the Volcanic Pistol and Varmint Rifle with these bonuses. To claim them all you need to do is visit a gunsmith in the game once you've reached - you guessed it - Chapter 2. The bonus weapons will be present in the catalog for free.
The stat boosters that come with the special editions (to Arthur's stamina, health and Dead Eye cores) are accessed through the Settings menu, but they're toggled on by default - you can switch them off if you prefer.
Rockstar makes things interesting in terms of you receiving the Treasure Map too - it's not gifted and you actually need to find, start and then finish a particular mission in order to get the map.
You need to do the mission "Le Tresor Des Morts". To start the mission, head north of Flatneck Station to find the burned village at Limpany. Head to the jailhouse and search the two corpses of the bodies in there in order to find a map that will begin the mission. As a bonus, if you search one of the burned out shacks in the village you'll find a strongbox to loot.
If you're interested in how you can unlock the western area of the map which is a callback to Red Dead Redemption, check out this guide.