Don't worry, Singapore is only a city state, so it's small and the city is well planned so you cannot get lost or confused.
The attraction for tourist is mainly in the south where the Merlion Park,the Esplanade is where you can view the city skyline and it's near Singapore Rover, so you can dine by the River ar Boat Quay and Clarke Quay.
YOu can also go to Little India and Chinatown which both have distinct cultural flavours and interests. You can also visit many museums nearby too.
You can visit the Botanic Gardens with the famous Orchid Gardens which is near Orchard Road, the shopping belt of Singapore.
You can visit the Singapore Zoological Garden which is very good and well planned with many animals, then walk to the next site to visit the Night Safari to view nouctural creatures.
You can also visit Universal Studios on Sentosa Island which also have many other wartime and interesting attractions.
You can also visit some heartlands to see how the local live , that is if you have time. Visit Toa Payoh, Clemeti, Bedok, etc.