The general rules of thumb with toilet training is to take them out:
• After every meal
• After a big drink
• After a nap
• After playtime/zoomies
• First thing in the morning
• Last thing at night
• After a training session
• After a chew or brain game
• Once an hour throughout the day
Feeding their last meal just before bed, will help them to sleep in longer in the morning, but can run the risk of overnight poop-explosions. Try to avoid repeating their toilet cue word whilst you're out with them, ask once, wait a few mintues then ask again.
When they do go to the toilet, make it a celebration with a big exciting cuddle party and a treat with "good, toilet" (or the word that you use as a toilet cue). This will encourage them to go to the toilet when asked to do so, as they find your praise very engaging. If they don't go within 10mins, bring them back inside and pop them in their crate for 10mins (to contain any possible accidents), then try again until they go.
DO NOT tell them off or make a big deal out of accidents inside the house, they don't understand why you're upset and just think that you're telling them off for going to the toilet in front of you. This will discourage them from going to the toilet, in front of you when outside and delay potential progress with toilet training.