Beginner in F5 ASM

ASM protects the traffic via a virtual server. You first have to configure a virtual server with SSL termination. The BIG-IP has to decrypt the traffic in order in inspect the traffic. After the virtual server is created. You bound the ASM policy to the virtual server via the security tab.

I would create a ASM policy via the rapid deployment template.  Once the policy is created select the correct applications that are being protected.  This helps to install the correct attack signatures. 

Also make sure that you have learning enabled for the policy.  The learning engine is a large aide for building the policy when you have no knowledge of the application you are protecting. I recommend keeping the learning enable with manual acceptance enabled all the time. I speeds up updating the policy when application developers forget to tell you about changes to the application.

You should also play with BOT protection.

WAF are very different than network firewalls. They require understanding of HTTP and other application protocols. An example of web content is java script / ecmascript. ASM will inspect java script content for attacks.  

You may want to take a F5 ASM traning course. The nomenclature used for ASM is different than what is used in general networking.