To do hair combos on Roblox, open Roblox on a computer using the Chrome browser with the BTRoblox extension. Log in to Roblox and go to your avatar.
Select the first hair you want to use. Equip the hair, then open its marketplace page and copy the asset ID from the URL.
Next, go back to your avatar and click on the “Advanced” button. In the asset ID box, hold down the Ctrl key and press V to paste the ID.
For the second hair, repeat the steps: choose the hair, copy its asset ID, and paste it in another asset ID box in the “Advanced” section.
Finally, click “Save” to apply the changes. Now, you should see your avatar wearing both hairs together. Note that this method only works on a computer with the Chrome browser and the BTRoblox extension, not on mobile devices.