Complex sentence: It dissolved in late 1986, when Studio Ghibli was formed and a lot of their animators went to Ghibli, thus making this studio the birth studio and start of Studio Ghibli.
Split into simpler sentences: It dissolved in late 1986, when Studio Ghibli was formed and a lot of their animators went to Ghibli. Thus making this studio the birth studio and start of Studio Ghibli.