How shoud I start to FPGA?

Hi friends ,

I'm new with Quartus and I have a DE0 Nano SoC . I have some problems with them.I need sources(pdf,e-book ,webside...) to learn with respectively.Everything is so messy on the internet I need with respectively,I'm used to use ARM Cortex but this is different,so complicated for me for now .For example I can do simple examples without clock signals but if I use clock with .sdc file , it is not working ,also I dont know what the IP is .Like you see ,I need all information like C or C++ books for example Dietel .I'm waiting your helps.

Thanks