Transition to big bed

Hi there! W had a good schedule with the crib and sleeping on her own for a long time. Baby2 is due any moment and we started the transition to the big girl bed. So far when she woke up in the crib she managed to sooth herself get back down and continue sleeping. Rare occasions where we had to intervene. Currently doing the "we lay with you time to sleep" and once she's asleep we remove ourselves from the room. Most nights she sleeps and stays in. Some nights she has wake ups sometimes she settles, sometimes not so much. So we go back in and lay next to her till she falls back asleep and we remove ourselves again.

I know we should not do big changes either right before baby2 arrives. But I felt it was important to playfully get there and she took it quicker than we thought.

But how will we train her about the you've to stay in bed instead and not walking to the door crying etc ? Should we continue with this method until she actually understands more? She's only 17 months.