I suggest the following. Create an Excel or equivalent worksheet that contains two columns.
Column A is the word you've come upon that you haven't memorized yet either in meaning,
usage, etc. Column B is a full sentence with that word highlighted, capitalized or some other
method where you will clearly see the word within the phrase. Personally, I suggest getting
at least 2 if not 3 usages of that word. Two reasons, one, it expands your vocabulary and two,
it allows for the fact that many words have double meanings.
Ahora, allora, so, we have this list which will grow over time. What's nice about this "dictionary"
is that it's your personal dictionary specifically geared towards your areas of interest.
As far as adding a new word, etc, goes, you can either manually find the location within the
file by finding the correct row manually, or, you can add it to the top of the file and use the
sort function to have it place the word for you in whichever sort method you prefer.
Hope this helps.