Potty training helpp

Hi everyone, we’re having a problem with our 4-month-old puppy. He’s gotten used to using pee pads, and we can’t manage to get him to go potty outside. Most of the time we take him out for about 20 minutes, come back home, and he pees as soon as we walk in. He also pees immediately after eating, but taking him out right after meals doesn’t always work either. The only times he might pee outside are right after he wakes up and hasn’t gone during the night, but even then the chances are very low. What can we do? These are his first real outings, so he spends the whole time sniffing the ground, eating leaves and random stuff, and going crazy whenever he sees someone. Helpp pls