The journey of a thousand miles begins with a single step. That's how IPT is. You just have to try, and then you'll be hooked. No matter what your reasoning for wanting to do this, the biggest barrier will be your own fears of failure, or of being viewed as a loony. I know that I certainly felt silly the first time I held my 4 day old son over the sink and grunted to try to get him to poop. But I tried it anyway, and lo and behold, he pooped right there on the spot.
So, to get yourself started, just try it. You can either hold your baby on a potty, or you can hold them in your arms and hold them over the sink. The latter is my preferred method for younger babies who can't sit up just yet. The following picture gives you an idea of how to do it.I highly recommend trying this for the first time right after baby wakes up from a nap. It can help you to build confidence if you have a successful first try. When baby is waking up, take her to the potty place/sink, hold them over it, and cue them. Say sssst for pee, and grunt for poop. Yes, you'll feel silly, but do it anyway! Don't hold them there for forever, let your intuition guide you on when it's been long enough. In the very early days, we knew potty time was over when their feet started turning purple. (=
Don't get caught up in the whole needing to have your baby diaperless or in cloth diapers thing for now. It's perfectly fine to start out in disposables. To tell you the truth, I have less success when trying to have a "diaper free" or "nakey bum" baby. Maybe it's the motivation of not soiling a diaper that we'll have to throw away or wash that helps me to tune into my baby's cues.