Cloud computing fundamentally requires a network. To understand the basics of network and infrastructure security, you will need to understand IP (Internet Protocol) networking. If you don't know what 192.168.1.1/32 means, you may need to review some IP networking.
A basic introduction to some of these can be found in this video. If you feel unsure about your knowledge level, consider reviewing the video, even though it does not cover all of the topics above. It is less than 10 minutes. Please put additional questions in the discussion session. We are here to help you.
The following video explains CIDR for IP version 4, which roughly speaking is a way to separate networks into subnets. The video is a bit dated, but not wrong or obsolete. Before viewing this video you should know that 'octet' is a different word for 'byte' (8 bits). It is worth watching the full 14 minutes, as CIDR notation is explained at the end. CIDR notation is what is used in security group rules in almost all IaaS providers.
Finally, you should know that the official private IP address ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 (if you understand that, you don't need to watch this video).