How do i change the radiator on my 2008Pontiac G5?

Hello, the best thing for you to do would be to acquire a shop manual at your local parts store or online that will give you step by step instructions to refer to. This may or may not be a job for a "do it yourself" person, as the damage may prevent proper installation of replacement parts. If you do not replace the bent condenser also, you may have fitment issues. Further, if you replace the condenser, you really should be licensed to handle refrigerants. Lastly, when your replacement radiator is installed, are you aware of the proper procedure to purge air out of your cooling system and refill the coolant to the proper level? This is not to be taken lightly as it's a very important step, and failure to execute properly can cause engine damage from overheating. Carefully consider whether it's worth it to undertake this job.