I assume you will move to Montreal, as that where mostly all English school programs in the province could be found.
Here it is a list about every English program in Montreal, by the English Montreal School Board.
https://www.emsb.qc.ca/emsb/schools/secondary/school-search
https://az184419.vo.msecnd.net/emsb/emsb-website/en/docs/2022-2023/list-of-schools-22-23.pdf
Although the amount of places for English speaking students have been capped in the province recently as a new law have passed.
Besides that point, you can't just enroll them in an English speaking program, you must check and apply for a "certificate of eligibility" if you are going to enroll them in a public school. You can start from there, applications are processed within 10 days . If they are not eligible you should think about private schooling or just a French school, some have integration programs that could ease their time living in Quebec.
http://www.education.gouv.qc.ca/en/parents-and-guardians/instruction-in-english/eligibility/
Regarding what school to go, as in ranking, it is dependent on where do you live, as you can only attend a public school that is in the same district as you, with rare exceptions to that (usually you are put in a waiting list). These are the districts covered by the Montreal English board.
Côte-Saint-Luc, Hampstead, Montréal (except Lachine, Lasalle, Pierrefonds-Roxboro, Verdun), Montréal-Est, Montréal-Ouest, Mont-Royal, Outremont and Westmount
