Can anyone please help to study a simple case of GR.?

consider a following situation,where a person A is on earth and another one B far from earth where his proper time is not influenced by earth's gravity field.now whats time flow felt by A wrt A and wrt to B.?
I get the answer for it but i need a explicit explaination..Is there any link where I can get formulae for this using GR.??thanks in advance

 

what does this mean----
"If a distant observer is able to track the light in
a remote, distant locale which intercepts a time
dilated observer nearer to a more massive
body, he sees that both the distant light and
that distant time dilated observer have a
slower proper time clock than other light which is coming nearby him, which intercepts
him, at c, like all other light he really can
observe. When the other, distant light
intercepts the distant observer, it will come at c
from the distant observer's perspective."