Son Tao's soul ended up within the body of a being called Sadalla. Sadalla was not a name that was unfamiliar to Son Tao, since Saiyan history was part of his education as a descendant of Saiyan royalty. He knew that the saiyans had originally come from a planet called Sadalla, and that this was also the name of the royal family of that planet. Planet Sadalla had been destroyed by a civil war among the saiyans, and the remaining population had fled to the inhabited world of Planet Plant.
The planet was already home to an intelligent race known as the Tuffles, and Son Tao knew that the Tuffles would not escape the bloodthirsty tendencies of the saiyans. Son Tao gained some knowledge and memories of his new body, but he was fundamentally unchanged by them. Sadalla, the body he was in, had been an outcast among the saiyans. He was a vestige of the old royalty that, due to their inability to manage the saiyans in the first place, had cost them their planet. Sadalla had died as a lone wanderer with no friends or family to speak of, and Son Tao was unwilling to do the same.
Son Tao chose not to use his old name, as he couldn't change his new body's physique, and none of the other saiyans used family names. Saiyans were expected to be independent practically from day one, so family connections were basically meaningless. Son Tao chose to embrace the name Sadalla, and began training to reach the same form that had killed him.
The road he faced was challenging, but Sadalla had plenty of advantages that helped him. Unlike the other saiyans, he was not arrogant or bloodthirsty, which were the two traits that had done the most harm to their race. He had also undergone rigorous martial arts training in his former life, and once he adapted to his new physique, he would be significantly stronger than other saiyans of his power level. Sadalla also knew about how to reach Super Saiyan, which was believed to be a myth by the vast majority of saiyans. Sadalla was weaker than he previously had been, so he would need to train a lot before he could reach the level of physical strength needed to sustain the Super Saiyan form.
Sadalla had a very rudimentary plan. He needed to accrue a lot of food and a lot of time. The best way to do that was to head to a planet with plenty of food, and basically no strong sentient life. With those criteria, he knew Vampa was the best bet. If he didn't strand himself there by accident, at least. With that settled, Sadalla went to his former home in one of the saiyan settlements, and took a space pod to Vampa. Most saiyans didn't take any notice of this event, but a few in his settlement were willing to at least say goodbye to him as he left.
Since it won't ever truly be relevant to the story, I'll use this place to say that Son Tao's original physique was closer to Vegito's physique, while Sadalla's would be a bit like a bulkier Gogeta. Something like a Broly-Gogeta fusion.