Here is the correct sentence you should probably use:
This is strange and incorrect:
I woke up early today to ascertain the usage of a word; however, I have not received a clear explanation.
This is much better:
When I woke up today, I thought I was going to learn a new word and how to apply it or use it in a sentence but it's still not clear. And no one has explained it to me as of yet. But I'm hopeful.