1. Open steam and enter your own library.
2. Find gta5 and choose to run the game to enter online mode.
3. Enter the game and find the style in the menu.
4. In terms of style, choose accessories.
5. In the attachment menu, select the helmet.
6. Find the thermal imaging helmet in the library. After selecting the helmet, you can see the enabled options in the lower right corner of the screen. When enabled, you can see the effect.