Linkers do not simply join sentences together. They also show how ideas are related.
"TO" - Example - Most people work to earn money.
"TO" infinitive is used here to express purpose. Also, IN ORDER TO and SO AS TO are used in formal situations.
Example : The government took these measures in order to reduce crime.
IF, UNLESS, IN CASE
These words are used to express a condition.
Example : You won't learn to use a keyboard properly unless you practice.
BUT, ALTHOUGH, INSPITE OF
These words are used to express the idea of contrast.
Example : The jacket was nice but it was too small for me.
BECAUSE , SO
Because is used to express the reason for something while so is used to express the result of something.
Example : I turned the heater on because it was cold.
It was cold so I turned the heater on.