Whilst inside Minecraft:
Open up the menu
Navigate to “Options”
Then to “Resource Packs…”
Then to “Open Resource Pack Folder”
Now place your .zip file into the new window that has popped up
You can now close the window.
You should then be able to click on the arrow to move it over from the “Available Resource Packs” to “Selected Resource Packs”
If the pack doesn’t show up, just exit out of the menu and navigate back.
Now it should appear under the right hand column as shown below.
From your desktop:
Press [⊞ Windows] + [R]
You should now see this window pop up.
Type into the text box “%appdata%” then hit “OK”
This will now open a window. You now should look for the “.minecraft” folder.
Once in the .minecraft folder, look for your “resourcepacks” folder and open that.
You can now place your resource pack into this folder and close the window.
If you need any help, please message me in Discord, or post in the relevant channel.