To set one, assuming that you can get a good-looking pass, you need to
1> beat the ball to the spot;
2> wait for your Middle Hitter to jump up;
3> push the ball to his/her swinging palm.
If you "throw the ball up" before s/he reaches the hitting spot, it would be a "2", which is one ball higher than the "1" set.
There are other sets, but typically running at mid-adv levels are:
a) "1" (some call "51"). The setter sets the ball right in front of him (or on top of him), with the ball just over the net;
b) "2" (some call "52"). The setter sets the ball right in front of him (or on top of him), with the ball about "two balls" (some say two feet) over the net;
c) "3" (some call "shoot"). The setter "shoots" the ball almost parallel to the top of the net (2-3 feet higher than the top of the net) to the far left end for the hitter to swing a quick hit.
d) "4" (some call "14"). The setter sets the ball four feet higher than the net, with a curve, to the far left end for the Outside Hitter.
e) "5" (some call "95"). The setter sets the ball five feet higher than the net, with a curve, to the far right end for the Right-Side Hitter.
f) "slice". The setter sets the ball to the spot behind him, about 2 feet hight than the net, and the middle hitter runs to the spot and hits the ball with a one foot jump.
g) "ten" (some call "pipe"). The setter sets the ball high-high on top of the 10-ft line, for a back row player to hit... from the back row.
h) others...
By the way, different teams could call different numbering for their plays, and listed above are just some typical calls used in west coast (at least.
Lots of teams mark the net with 9 hitting spots, with 1 at the far left, 9 at the far right, and the setter at 6. They then put the hight of your set into the second digit and make it a call, such as 13, 14, 51, 52 (just mentioned above).
Hope these helped a little bit.