Here is the verse on the web with multiple meanings.
This is informative.
The song on youtube: https://www.youtube.com/watch?v=m5G_ilgDcLk&list=PL1_mTE9wjxTk4PIkF4kQdGTOgdfYsDw3x
Here is my meaning to the last portion of the song.
Om bhuh om bhuvaha om svaha om maha om jana om tapah om satyam
Om — Om
bhuh — on this earth that we are upon (our past)
bhuvaha — this earth that is our vehicle (at present)
svaha — the self observes (the atmosphere, or the future, the spiritual adobe)
maha — the greatness of it
Jana — the people
tapa — the burning
Om satyam — Om that truth revealed to us (of our life)
Om tat sah vitur varinium
Om that with the manner in which we worship, the sun is the bestower of that light.
virgo devasya dhimahi
Vigro or Bhargo? we are rotating around the god devasya that we should meditate upon.
Dhiyo na prochodayat
with intelligence (with practice of prayer) that you not tell the world
Om apo joytir raso amrutam
Om do not stop from the light the emotion of the immortal nectar (understanding of this depends on what a stage in life, wisdom and spirituality a person has acquired in life)
bhrama bhur bhuvasvaro
God of this earth, earth as our vehicle self observes.
On this earth we are upon that is our vechicle, the self observes, greatness of it the people, the burning to that truth
That with the manner in which we worship, the sun is the bestower of that light. That we are rotating around, the god (sun) we should meditate upon with intelligence (practice/prayer) that you not tell the world. Do not stop from the light (the sun God, that delivers us from truth of all things) of emotion of the immortal nectar of God of this earth, that earth as our vehicle the self observes.