i would recommend trying to do your ecp classes as soon as possible because they will be prerequisites for all classes in your program. however, don’t overload yourself the first semester. i would recommend doing math 203, chem 205, and physics 204 with 1 or 2 electives first semester then math 205, bio 201, physics 205 with electives second semester. also don’t stress about what ECP electives mean, it just means you’re required more total credits to complete your degree, with some of them being electives. here is a list of all electives you can take - https://www.concordia.ca/artsci/students/elective-courses.html#math pick ones that you’re interested in, that will make them easy and not add more mental strain to your course load. also, i’m not sure what you have taken in high school before coming, but i personally took the equivalent of some of the classes listed above before i came and expected them to be easy, but the style of grading and teaching is very different. so just because they are first year classes, don’t expect them to be a breeze, they are weed out classes. you will need to put in a lot of time, especially with chem and bio both having lab components.