Hi
here you go
1-you may read the tuts link from main caffe site one more time specially 3 first
2-the problem you have with cpu will done if you change last line of the solver.prototxt ,solver type from GPU to CPU
3-i'll be glad if someone say's how long it take to do imagenet on cpu mode (simple core i7) but seems for now that isnt good choice for you,try by mnist and your own simple dataset
4-simple classification is to prepare the model architect for both train and val ,solver and a simple mean file,next you go by preparing the lmdb( level db or image folder) and related .txt containing categories then fire the train from caffe/tools.
keep up the good work