How do you stay in your lane when there aren't any lines on the road?

There are some very basic things you need to know about this situation.

If there is room for two lanes there are two lanes.

The centre of the road is the division if there is only room for two lanes of trafic.

The police will ticket and assigin blame based on tape measurements if there is a crash.

If there is no lines you should try to be 1 foot ( 30 CM ) from the 3dge of the road and well clear of the centre if possible.

If you have to be near or over the centre drive slow and carefull.

Be polite to oncoming trafic.

And finally you should do all the above easily if you are able to pass a basic driving test and get a licence, its just care and practice.