PL is typically set as the "Tone" (CTCSS). Some radios show this as a "T". This is needed for FM on non-Yaesu rigs.
DG-ID code is 14 and is found under the GM settings on Yaesu rigs. This is used for both RX and TX digital modes. Default is 00, so changing this is required.
+ refers to the positive offset frequency. It is 600KHz above 144.570 or 145.170 MHz.
Setting a positive offset will set your rig to transmit at 145.170 MHz.
These settings are necessary in order for your transmission to be heard by repeater users.