Requirements:

-An internet connection

-One of the following devices with a copy of Minecraft installed:

Android Device, iOS Device, Windows 10 PC, or Xbox One

Step 1:

On your PS4, download the Minecraft Classic Textures from the Minecraft Store. After it has downloaded and installed, delete the Classic Textures through the global resource packs screen.

Step 2:

On your mobile device/PC/Xbox, install the Minecraft Classic Textures from the Minecraft Store. After it has downloaded and installed, delete the Classic Textures through the global resource packs screen.

Step 3:

On your mobile device/PC/Xbox, import the resource pack you want to put on your PS4.

Step 4:

On your mobile device/PC/Xbox, exit Minecraft and download the following manifest.json file through your web browser:

Download manifest.json

Step 5:

On your mobile device/PC/Xbox, copy the manifest.json file from your Downloads folder to your clipboard and locate the resource_packs folder. The resource_packs folder can be found at the following locations depending on the platform:

Android:

/sdcard/games/com.mojang/resource_packs

iOS:

Apps/com.mojang.minecraftpe/Documents/games/com.mojang/resource_packs

PC:

C:\Users\(your pc username)\AppData\Local\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\LocalState\games\com.mojang\resource_packs

Xbox One:

Watch this YouTube video

Step 6:

Once you locate the resource_packs folder, locate the resource pack that you installed on your mobile device/PC/Xbox and paste the manifest.json file in that folder. Be sure to overwrite the existing manifest.json file.

Step 7:

On your mobile device/PC/Xbox, launch Minecraft and apply the desired resource pack to any world. Start the world. Note that the resource pack name may say "pack.name" and the description may read "pack.description".

Step 8:

On your PS4, join the world and make sure to download the texture pack when it prompts you. Once you join, you can leave the world.

Step 9:

On your PS4, apply the Classic Textures to the world you want the custom resource pack applied on. It will ask you to re-download the Classic Textures. Click Download. When the world loads, you will see that the custom resource pack loads and not the Classic Textures.

Tips:

-You can delete installed (cached) resource packs through the Storage tab in Settings in Minecraft.

-When updating a resource pack, delete the custom one in the Storage tab and the Classic Textures through the global resources screen. Follow this tutorial again from Step 1.

-You may only apply resource packs per-world using this method, not globally.