Basics for keyboard playing, such as hand and finger placement, can be learned from most any basic skills handbook found in libraries or sold online.
Another option is to take lessons in person.
Others have found it suitable to teach themselves to play keyboards; they start their journey solo or with the basic helps provided above and tenaciously stick to the motto "I'm Gonna Play This Thing!"
Those who have a basic sense of melody and some sense of rhythm, and who are willing to try to teach themselves, might begin this way:
(1) Start pressing keys---any keys, 1 or 2 at a
time, using only middle finger and thumb,
one or both hands at a time.
(2) Repeat any note patterns heard
(3) Slow down or speed up the tempo while
repeating the patterns
(4) Experiment with other rhythmic
movements of the fingers all over the
(5) Try to add notes to any melodic phrase
or phrases created
(6) Maintain a sense of humor---you're
probably going to need it
(7) Don't give up
From there it's a step forward to fingering chords, which info is available as stated above.
Of course, playing simply and playing in a more advanced style are different items.
But from the first, the main motto should be, "I'm gonna play this thing!"