I would start by teaching the phrases separately with visuals:
Tengo frio
Tengo calor
Here is a video of one of our kindergarten students singing the song:Tengo frio,
Tengo frio,
Tengo mucho, mucho, frio.
brrrrrrrrrr
Tengo calor,
Tengo calor,
Tengo calor.
(repeats)
You can sing this song indefinitely which makes it great to sing during transitions (like lining up or cleaning up.)