You either sign up for a month to month subscription or a yearly subscription. They have many plans for all the distances from sprint to full in 3 different levels from low, to mid and high volume plans. You can pick and start whatever you want based on what distance you want to focus on and volume. Each plan follows a base, build and speciality phase, which for most distances are 8 weeks each. You can choose when and where to start a plan, and can also move workouts to wherever you want to do them based on your time schedule. You also don't have to follow a plan and can pick any workout you want based on your needs and preference.

Ive been using TrainerRoad for the last 4-5 years and find it to be of great value. I just follow the bike workouts though and do the swimming and running on my own. Partly because they are more focused on the aspects of cycling, and I personally feel they haven't put in the same amount of time into their swimming and running workouts, but hopefully in the future they will. I would suggest starting out with the low to mid volume plans with whatever distance you want to focus on, especially if you haven't done structure indoor workouts. It takes a while to get use to because there are lots of hard/challenging workouts. But if you can be consistent with the low or mid volume plans, or if you just decide to cherry pick workouts instead of following a plan, I find its a great product to use.