As only SingTel monopolies the fixed phone business, you have to choose SingTel.

First go to any of the post office to get a free application form. The form has the SingTel logo, easy to recognize.

Fill the form, go to post office counter to submit. You may be asked to show your IC.

Wait for them to call you ( don't know what happen if you don't have a phone). Usually it would be one or two days after you submit the form.

The caller will tell you when it will be activate, usually anotehr one or two days later. On the phone you will also be prompt a phone number, you can ask for some other choices ( I got 3 numbers to choose). You will be asked does your house have the phone line socket on the wall (usually it would have).

After the call, what you need to do is just plug your phone into the socket and start to use it after the activate time. If your house doesn't have that phone line socket or has problem using your phone after the activate time, you might have to call them to install/check it, which you have to pay.

Good luck!