Sure
You need a compiler first, and some program to edit the .cpp files. This can be notepad, but there are also really cool development environments programs available, with syntax highlighting, colors and a lot of things. The best of them for Windows is, IMO, Microsoft Visual Studio (MSVC). You only need the Visual C++ part of Visual Studio anyway.
Then you must have noticed a readme coming with the HPB_bot template. Read it (take the time to), even if you don't understand everything, it will be useful for you to understand a bit of what's going on.
Then you can try to compile the bot for one of the already supported mods, such as Half-Life deathmatch for example. Compile the bot, change a few things in the source code where you understand what it's about (for example, change the reaction delays of the bots, or try to make the bots say something on occasion) - browse the source code, notice how it works, copy and paste little blocks when you know what they do, do this for some time and you will improve the bot a bit, but foremost you'll be learning how C/C++ works.
Once you get a little more familiar with the code (not necessarily to know what everything does, but at least when you know roughly where such or such function is located in the .cpp files), you can try to port the bot to your Rival Species mod. To do so, read the readme again and try to follow what it says step by step.
The best place for discussing about bot coding is the bot coders forum (I'm moving the thread there, no objections ?) ; we welcome beginners so don't hesitate to come and ask whenever you've got a question !