set forth on

set forth on something

 and launch forth on something 
1. Lit. to start out on something, such as a journey. We intend to set forth on our journey very early in the morning. What time will you launch forth on your trip?
2. Fig. to begin presenting a speech or an explanation. As soon as John set forth on his speech, three people walked out. Every time he launches forth on a presentation, it's a half hour before he shuts up.
See also: forth, on, set
References in classic literature ?
A MULETEER set forth on a journey, driving before him an Ass and a Mule, both well laden.
As he wanted his breakfast by that time, having set forth on a crust of bread, he stopped at the next roadside tavern to refresh.
They set forth on the walk back; and the others, with one exception, straggled after them at various distances.
Isaac acquiesced with a deep groan, and set forth on his journey, accompanied by two tall foresters, who were to be his guides, and at the same time his guards, through the wood.
When the Prince set forth on his travels it was but natural that this devoted couple should accompany him, and accordingly he started with them and attended by a numerous retinue.
The next day my mother and I set forth on the first stage of our journey to the south coast of Devonshire.