Trig Ratio help with learning

http://1drv.ms/1GwTyXK

The above link takes you to two pages in my GCSE Further maths textbook. This is a CCEA bridging course for GCSE students going on to take A Level maths. They take their GCSE maths a year early and then this GCSE Further maths in the normal GCSE year.

I'm learning maths as a 55 year old to help my son. I have now come to these Trig ratio questions. Normaily I look at the text book and then go to exam solutions, hegarty maths and m4ths.com (UKmathsteacher) on you tube as I find it easier to learn by watching than reading in most cases. But with these Trig ratios since it is a bridging lesson I cant seem to find a few videos that will start where the textbook starts and move on from there.

Any help in identifying the right videos (or a phrase that would give better search results) would help me lots......many thanks in advance for any help, advice offered.

Does the attached file help at all? please let me know.

Had a quick look and it seems as if this will be a real help. I will print and enjoy some bedtime reading. I appreciate your thoughtfulness.....thanks