The links from the page that you posted are not useful at all for your role. This page for best practices leads to some marketing/sales related content which targets potential customers. As a system administrator you are not the intended audience. On top of this, they talk about S/4HANA Cloud where system administrators do not typically handle installations and upgrades (unless you are a SAP employee, of course).
SAP Activate is an implementation methodology. While it is important to be aware of the differences compared to ASAP, specifically for Basis experts the impact is probably not that significant as for functional consultants and developers.
The actual link to Best Practices is https://rapid.sap.com/bp/ . At least there you can find some useful information on configuring the system, but it is scarce for your specific role. You will probably prefer to use the documentation from the installation guides. Most of the content, as I mentioned, is beneficial for functional consultants - there are configuration guides, document templates, test scripts, process diagrams, etc.
The Roadmap Viewer page might be useful is certain scenarios - there are links to document templates and other documentation, but not in the sense of doing the actual work as an administrator, it is more about when to do what and how to document it. This is just my opinion, some will probably disagree, but to me this resource is useful mainly for project managers, as a consultant I have not seen anything there that speeds up my work or makes it easier in any way.
Learning Journeys - this is nice and it can help you become better at what you do... if your company or you can afford the Learning Hub subscription fee or if you plan to take a certification exam.
1. You could have added at least the URL from where you took the screenshot 🙂
2. I am not able to understand what it is exactly that you do not understand about SAP Best Practices, please be more specific.
3. How you can utilize Best Practices to your interest depends on what is your role in the project. Most of the documentation is useful for functional consultants, but there are also some building blocks that are typically done by the technical team, e.g. Situation Handling (31N). From your profile it seems that you work as a system administrator, so probably most of the content will be irrelevant to you. Still, there are some links to documentation, which could save you a bit of time.
i took the screen shot as below.
url is here
To be more specific i want to know can i use the sap best practices for SAP Administrative tasks like SAP ERP installation, administrator, Database administration,installation.
Could it be used for a SAP Basis Guy.