If you want to make money from Blog. The first thing you should focus on the Content.
If your content is good then people will engage with your blog otherwise they simply left your blog.
second thing is you should promote your blog in different platforms otherwise people wont know about your blog.
If you done all the things correctly then people will come to your Blog and they will engage with your blog then you can add Adsence which helps other business people to post adds in your blog.
You can not get money instantly by writing blogs. It takes a little time.