To complete the tutorial, you have to follow through the steps it gives you and eventually complete the tutorial aspiration for the career you chose. In this instance, I chose the Athlete aspiration. All of them have the same steps, they just trigger unlocks for items for that particular career (athlete, cook, painter, trend-setter).
Once I completed the aspiration tasks (various household things, get a promotion, travel to the park, meet some new sims and do some fishing) I had completed the tutorial.
It first asks you to choose a new aspiration, and gives you a screen with 4 choices -
Fabulously Wealthy, Soulmate, Architect and Devious. I chose Soulmate.
Next it says that Alex (the tutorial roommate) is moving out to go help other new players "Bye Alex!" (in tutorial audio). Alex exits the house and disappears. Then it introduces Build Mode, Gallery, and the Help Lessons.
Then another big screen to finish out the tutorial - "What do you want to do now?" - with 3 choices:
Add a New Sim to this Household (adding a second sim to this household will make a richer experience); Continue Playing (the tutorial is over but you can continue playing this household); Start a New Game (Start Fresh with New Sims, a New Home and a New Story). I chose to add a new sim.
Choosing to add a new sim immediately loaded CAS. In CAS, Alex, the tutorial roommate that left, was a member of the household along with my sim who was active in the editor. If I had just gone through the tutorial, I would have had a hard time figuring out how to add anyone to this household, and might have thought this was my "new sim". But I decided I would do what I was supposed to do, to test the expected workflow so clicked on the button to add another sim and did so.
Once I had added the sim, I did not do anything with Alex, because I thought maybe she was queued to leave anyway AND the tutorial said to add a sim. When I accepted the sim and went back to the household, Alex was there and part of the household with my other 2 sims. My original sim (Tim Tester) was reset back to 2/4 on the tutorial aspiration, the morning before he went to work and got the promotion, the last saved point. But nothing was locked like in the tutorial, and there was no audio or tutorial running.
It's important to note that I originally finished the aspiration after returning home - it prompted me to go home before I had met 3 new people or fished for an hour, so I quick introduced my sim to a few people and then "went home". There's a fishing spot right outside the house. Maybe @Rabbitzan12 completed the tutorial at the park, and that's why the sim couldn't go home or travel? Not sure, but I tried it again by completing at the park, but it did not exhibit those symptoms for me. I think there was probably more than one issue going on there.
I replayed the same game from the place where it kept throwing me back. When I paused and saved the game right after the help lesson, I was able to enter CAS without having Alex reappear in the household. Adding a new sim worked, and when I was returned to the household Tim Tester had a retraiting potion in his inventory, as well as all his gifts, he had the Over-Achiever trait from completing the tutorial aspiration, and his current aspiration was the soulmate one that I had chosen.
