In order to give two causes/reasons in one sentence, present the sequence with the stronger cause-effect relationship first, expressing the cause in the te-form or followed by で.
Then, add the situation that results from that, which has been expressed in the て／で phrase, using から or ので.
I smoked and was scolded by my doctor; therefore I have to quit.
I'm not quite sure what it means, so please say it again.
I got sick, so I didn't go to school.