I tried lot of time with various planes to use the autopilot locked on the ILS frequency,by clicking on Approach or APR switch on the autopilot gauge. Of course, the autopilot must be turned on and the correct ILS frequency entered !
In any case this is not very safe for your passengers as with big airplanes this system is very slow or do some over correction of the landing trajectory. The best is to try to follow the ILS signal "by hand". I play with Flight Simulator since 1990 and never could bring back to ground a plane with the autopilot.
SO, good luck and enjoy the fly (at least).
