I'm not a professioinal musician, just a hobbyist, but here are some tips. For starters, musical notation is a major hurdle that turns many newbies away, so I suggest starting with synthesia - it's a great app to learn with. You can buy/steal it, find midi files of your favourite songs or just watch pre-recorded footage on youtube, just search for "name of song synthesia". Piano is simple, really, just press what you're seeing and you're good to go. Most songs go melody on the right and chords on the left. So start with right hand only to get some results and satisfaction right away, then go for the left hand only and train to the point you're not really thinking about it, then try re-introduce the right hand. It's going to be hard, but at some point, maybe in a few hours, it should just click together. Later, you can learn the notation, but I highly suggest learning how scales and circle of fifth work and learning few more songs the newbie way before the switch, it will improve both your song learning ability and it's an essential part of learning musical notation anyway. Get a feel of the chords in different scales and try to jam with a simple 1-4-5 chord progression, after some practice you would be able to noodle effortlessly in any key, giving you the ability to easily learn and play along with most pop songs.
Another tip I would suggest for starters, is to hold the sustain pedal. If your piano has just only one pedal, that's the one, if it has three, it's the rightmost one, if you have none, like on a lot of electronic pianos - stick a paperclip into your sustain pedal port to short the connection. This will make your notes continue to ring even after you release the keys, which would make it more forgiving and will generally make it sound better. But later on, do release it and learn play without it, after all, release is important, it will sound muddy if you just hold it forever.