Entry is free, no tickets need to be purchased.
Cycling along the course is possible, bicycles intended for coaches can be rented through the organising committee by the team manager (email@example.com). No bike rental is organised for fans since Amsterdam has many bike rental locations. See also this site by the city of Amsterdam:
Food & drinks at the venue for visitors
There is no need to bring your own lunch or coffee to the course, a wide range of beverages and drinks as well as fast served coffee will be available for you.