Scalar Multiplication on Elliptic Curves
The typical way to do this is the double and add method.

You start with the binary expansion of the scalar $57_{10}=111001_2$

Then scanning right from left, for each bit you double and if the bit is set to $1$ you add.

With elliptic curves it would look like this:

$Q\gets\infty$ (or the point at infinity since it is the identity element)
$P_{tmp}\gets P$
$bin\gets [1,0,0,1,1,1]$ (i.e., the binary expansion of the scalar reversed)
for $i$ in $bin$:
$\ \ $if $i==1$:
$\ \ \ \ \ Q\mathrel{+}=P_{tmp}$
$\ \ P_{tmp}=P_{tmp}+P_{tmp}$
return $Q$