LFO 1 allows you to select different waveforms for modulating parameters. These are (from top to bottom):
The available LFO 1 Destinations are as follows:
By clicking this button you activate/deactivate LFO sync. The frequency of the LFO will then be synchronized to the song tempo, in one of 16 possible timedivisions. When sync is activated, the Rate knob (see below) is used for setting the desired timedivision.
Turn the knob and check the tooltip for an indication of the timedivision.