Even though your cat is in a new environment and is likely to want to explore, it is not the best thing to let them do straight away.
For at least 2 weeks it's important that your keep your cat inside the house even if you think they have settled in. This time allows your cat to bond with its new home and learn the layout.
Try to play with your cat and give it lots of attention to make sure they don't get bored during this two week period.
Once the two week period has come to an end then you are able to let your cat venture outside. When it is quiet, go outside with your cat and let them explore the surroundings a little.
If you cat is timid then it may take a longer for them to become used to the new area but if you accompany them outside as much as possible at the start then they should start to become more confident.
Always ensure that your cat has a form of up to date identification on them, whether this be an ID tag or chip.