Local Apparent Sidereal Time, is Greenwich Mean Sidereal Time adjusted for the longitude of the observer.
Either mean or apparent sidereal time may be used based on which your application requires.
$$
\begin{align*}
LST = SiderealTime + Longitude.
\end{align*}
$$
SiderealTime and Longitude must be expressed in the same units (divide Longitude in degrees to get hours).
Using Apparent Sidereal Time, yields Local Apparent Sidereal Time