How to transition from peeing on the pad to the outdoors living in an apartment

Hi all! I have a 3 month old mini dachshund puppy, she is now fully vaccinated so ready to go outdoors. I live in an apartment and have pad trained her really well, she always goes on the pad without fail. Since yesterday she has been allowed in the outside world and I’m struggling to work out how to get her to pee outside! She currently is holding it in until she gets home to go on the pad and I can see she is holding it in and is uncomfortable. This morning I took her to the outside area of my building (there is grass etc) and waited over an hour and still nothing even though I could see she needed it. After this I took a pad outside and she eventually peed on it after about 20 minutes. Does anyone have any tips on letting her know it’s okay to pee outside? When she went on the pad outside I gave her a treat and positive reinforcement but it still hasn’t clicked for her. Any advice appreciated 😊