Don't worry about blind keyboard navigation. As rhapsody in orange already said, this will come with time. At this stage, it is probaly best to memorize the piece you are working on. Don't be afraid to look at your hands and fingers while you play. This is necessary for developing your "body map" and "keyboard map". Those are fancy terms for the concept that you can move your body wherever you want without looking, and you know your way around the keyboard without looking.
When it comes to changing hand position, I find the so-called five-finger-positions to be the easiest way to navigate a piece, in fact most any piece, all the way up to advanced repertoire. The idea is to place the hand such that the maximum number of notes can be played without stretching the fingers. This would ideally cover the span of five white keys, but seven should be doable as well. So, if you need to cover the space of eight white keys, you should be able to get away with one hand shift. If the melody goes back and forth, so will your hand. For each hand position, pick a reference key and a corresponding finger that goes on it. For shifting the hand, simply move that one finger while keeping the hand in a natural, relaxed state. This way, the other fingers will naturally fall on neighboring keys. You then play all the notes under the fingers until you need to shift your hand again.
When learning a new piece, you could go through it and mark those notes where a hand shift occurs and which finger plays it. The idea is to have the lowest number of shifts.
Shifts fall into two categories. First, the hand may need to move a large distance, more than five white keys, so that there is no overlap between the hand position before the shift and the one after. These shifts are called "jumps". Second, the new hand position may cover an area that overlaps with the area covered by the previous hand position. In this case, there is a range of movement patterns that make such shifts very smooth. Finger substitutions are a set of such patterns, but it's probably too early to talk about them. Another one is the "thumb-under" technique for scale playing. This is probably the first hand-shifting movement that a beginning pianist will come in contact with. Unfortunately, it is a "bad" movement, in a way that the motions are awkward and unnatural. It should be avoided whenever possible.
Hope that helps
