how to use the words "however" and "though"

[Abdou]

Hi everyone,
I am a new user, it's my first time in tis forum, I need your help to improve my English. Please answer me.
I have a big problem to use the words however and though. I know their meanings but when I read them in the paragraph, I find an other meaning. Sometimes I find this (however) in the begining of the sentence with a meaning, sometimes in the middle or in the final of the clause with another meaning.
Please could you explain me how to use this words. When can I use it in the begining, in the middle or in the final phrase?
Thank you.

[Haihao]

I think your question is too big to discuss here. Could you please put it more specifically, friend?