The first camera I modified to take near infrared photography was damaged many years ago, I finally got another camera worthy of being modified and am in the process of doing so. Basically the infrared filter inside the camera situated before the CCD needs to be removed, after that you need to block out most visible light with a filter, in my case i’m using a 720nm filter I got from China. I actually bought 2 of them so I could sand down the base of one, and after gluing it to the camera, I could screw the 720nm filter on and off. I think I will eventually just fix the filter permanently and use the camera only for NIR photos.