Trying to potty train my baby !

My baby is 3yo, I let her roam around without pampers it was suggested by a few parents but she would literally hold in her pee for hours till I put a pamper on her. When I know it’s her nap time or sleep time I put the pamper on. Idk what to do Bc she won’t tell me when she has to pee or anything she is on the spectrum. I don’t want her to feel uncomfortable holding in her pee for hours it makes me feel bad. She sat on her potty earlier with her tablet n cookies but came off after about 5min with no peepee.

Update: if I just hover her over the seat, she would keep her legs straight refraining me from sitting her down like she doesn’t wanna touch the seat. Only if she feels like being cooperative which is rare.