Transition from Cot to Cot bed.

My 21 month old has started climbing out of her cot so to prevent an accident we decided to remove the side 4 days ago. First couple of nights she went down fine, nap time on the other hand was more of a challenge and I ended up singing her to sleep. But the last few nights have gotten progressively worse and nap times are impossible. (I’m 33 wks pregnant and could really do with her keeping the naps until baby comes). Slowly I am removing things from her room as I have found her in the dark climbing on things, sitting in her chair reading books, playing with teddies etc she doesn’t stay in her bed for more than 5 seconds. Before the side was removed she was having naps of 3 hours from 1pm until 4pm ish and she used to sleep well all night. I know consistency is key , but returning her to bed doesn’t seem to work, I try to stay calm and not say anything, but I’m beginning to struggle. Has anyone any advice? Thanks