First of all, Welcome to the Group, let me answer some questions for you.
How to Make a Blog using SEO:
To make a blog of which you can rank using SEO, install WordPress onto a domain, you can do this cheaply using some cPanel hosting and install Yoast SEO as your SEO Plugin. Of course, you need to know about SEO and how WordPress works but YouTube can provide all of that in short form, easy videos.
What is a Backlink?
A backlink is a link from one authoritative domain to another. The idea behind a Backlink is that it passes some of it's domain rating and authority to another domain in the form of a ******** backlink. Having a higher DA and overall standard that other sites is what allows you to rank higher, however, backlinks are slowly becoming replaced by other factors.
What is CPA?
CPA or Cost Per Action is a form of bidding within Paid Advertisement or also known as Google Adwords. This is where you bid a payment per action and whoever bids the highest, will be the higher result. This means, the higher the budget, the higher the ranking, usually. CPA is often cheaper than CPC as you pay per action and metric, rather than per click through.
What is a Suitable Niche?
Choosing a Suitable Niche depends on what you know about and what you are interested in. If you can select a Niche or Area that you know a lot about, you can create more content and a better website that appeals to the right audience. At the end of the day, you want to make sure that you know about a Niche and that you can appeal to the right audience, or otherwise people won't click and read your content.
How to get Traffic to your Website?
Getting Traffic to your website depends on your strategy and budget. If you want quick results, you can look into Paid Advertisement on platforms such as Google or Social Media. If you are willing to work for the results or even wait while someone else does the work for you, SEO is a great route to go down as it's more organic and can often be cheaper once the work is completed.
However, Traffic depends on your Niche and Topic. If you build a blog or website about a Niche that isn't searched, it's not going to get anybody searching. Make sure you do your Keyword and Topic Research first.