I think this is where you find the difference confusing:
You can use "else" to introduce the second of two alternative.
"I will have tea or else coffee."
"Yet" can be used as a conjunction to introduce a phrase that appears to contradict an earlier phrase. You could also use "nevertheless".
"it was dark (and) yet I found my way."
"It was dark, nevertheless I found my way.
You will find explanations of the meanings here: