[SE-4441] add reading the onboarding and trial period section to the things to start with
requested to merge hchandad/se-4441-clarify-how-course-weeks-maps-to-onboarding-weeks into onboarding
Description
The onboarding section from the handbook talks in details about how the onboarding period is broken down, thus i think prompting the newcomer to read the Onboarding weeks section would clarify it.
The change looks like the screenshot above.