This is presumably at a beginner/pre-intermediate level.
Don't confuse the learners by raising points that may well not occur to them. In many years of teaching, I very rarely encountered a learner who thought an apostrophe might be needed.
As to 'the boy wants' vs the 'boys want', make sure that you have covered the plurals of nouns, and that your learners understand this, before you deal with the third person -s ending on verbs.
IF any learners appear confused, you could show them:
I want, he wants.
The boy - the boys
The boy wants, the boys want
s is different from s.
Student or Learner