Questions about the Futur Simple
Q: Why is it je commencerai and NOT je commencera?
The "je" ending for the simple futur is -ai, not -a (-a is the ending for il, elle and on).
Q: Why is it je voudrais venir and NOT je voudrai venir?
Use the conditional with vouloir when indicating what you would like to do (in the same way that in English, one does not say "I will like to come")
Q: Why is it il verra and NOT il voira?
The future root for the verb voir is irregular (verr-)