1. Add some lubricant on the rim of the wheel. This should manage the amount of friction that will be involved during the fitting.
2. You will need to soften the solid wheel before fitting it:
3. Put it in a microwave and heat the tire for three minutes, checking it after every minute.
4. Once the wheel is soft enough, remove it and fit the rim into it. Let it cool for five minutes.
5. Fasten the nut and the other screws (while replacing the plastic cover) on both sides. This is basically the reverse of the initial process of removing the wheel.
6. Fill the hole on the wheel with some silicone to avoid entry of dust, stones or water.