When I went through it years ago, it was mostly about making sure you had all your paperwork in order - had the company sponsoring you provided the relevant information regarding the role and why you were needed, did your resume and experience match at all with the work being performed, etc. Basically I showed up with a list of documents and a very nice border guard looked it over and said welcome to Canada. Each time I traveled up there for work, the border guards were polite and professional. Each time I traveled home, I got pulled aside for advanced screening like I was a drug mule. Just loved all the America trivia questions and deep dives into the history of where I live, just so they could feel good about their jobs.