start easy build up, invest in one of the books that shows you what exercises use what muscle. Like Mens Health big book of exercises – very helpful http://www.amazon.co.uk/Mens-Health-Big-Book-Exercises/dp/1905744692
take music, warm up on tread mill and rowing machine or do an hour on road first
for strength try reps of 6 to 8, 6 or 8 times gives you 36 – 68. Improves strength not bulk. Weight should be 75 – 80% of your max.
Start light, use good form not jerking. Slow controled movement improves quality of exercise.
Warm up say 15mins, then alternate arms with core etc. If you cycle a lot maybe dont bother with leg exercise. YOu shouldnt need to do more that 45mins with a break of 2 to 3 days between sessions