$CDS_TOP_DIR is the root directory of cadence. alternatively you can use $MMSIM_HOME/doc/spectreRF/spectreRF.pdf, since $MMSIM_HOME is $CDS_TOP_DIR/MMSIM. for your post related to pll simulation, see $MMSIM_HOME/doc/spectreRFvol2/spectreRFvol2.pdf
The best tutorial is what cadence provides and can be found in the cadence installation folder. However, a very quick way is to use a vpulse to initiate oscillation, and then you the transient analyses