Here are the basic words/expressions that everyone needs to know. Once they have been mastered, you can focus on the other categories.
Play the game!
Grammar Point: Present Tense
The present tense of a verb is formed by dropping the -ar (or -er or -ir) of the infinitive and using the appropriate ending. For example:
trabajar ("to work") > trabajo ("I work"); trabaja ("he/she works").
For some common verbs, the middle vowel changes as well. For example:
poder ("to be able") > puedo ("I can"); puede ("he/she can")
dormir ("to sleep") > duerma ("he/she is sleeping").
You can find out more about the present tense of verbs here.