Live with what you've got for a year; simple maintenance only ( mow lawn, remove weeds.).
That way you'll see what grows and flowers in each season. What produces edible fruit/berries; what has autumn colour or is evergreen, what has branches /coloured stems that look good in winter.
Through the year, keep notes in a diary. Notice which areas in which seasons are sunny or shaded; soggy or windy, visible by neighbours or secret and private.
Make a list of what your family want from the garden ( play space for toddlers/ ball space for older kids/ sunbathing spots / quiet shade . Do you need space for a dog, barbecue, washing line, mending bikes, out door hobbies,? Would anyone appreciate a sandpit, pond, watching wildlife, bird feeders, fresh herbs for cooking? Home grown vegetables or flowers? Would you rather sit out on a lawn, paving, or deck? Does anyone have difficulty on slopes or steps? Or visual problems?
Meanwhile, take note around local gardens, what plants do well in the area. There's an app which can put a name to a plant photo.
The commonest problem novice gardeners (and homeowners) make, is rushing to recreate something fashionable on TV which doesn't actually suit their own family or lifestyle or climate. Better to take your time observing.