Welcome to the forum and it's great that you've walked the DIP Lite course. You can indeed start blogging in order to ask for a sponsorship to walk the DIP Pro course, you can look at the rules here: DIP Pro Sponsorship Program
And a blog is a website where you are able to write in it and share with anyone that has access to it - whether you decide to make it public or private - and in the context of this process, it is used to share the aspects/points that you go realizing, discovering, working on in recognizing who you are as your mind, how you can practically create a point of change in your life and so, share the feedback of doing so. Other times blogging is also an open space for giving perspectives on a particular topic you'd like others to read on. So it becomes your own website where you write and everyone that finds it or has the link to it can read and follow it.
I recommend doing a search in your language if you'd be more comfortable - on youtube for example, placing the question 'what is a blog' and I'm sure there will be videos that can assist you in expanding these explanations.
Usually most here use Blogger or Wordpress to create a blog, however there are many options out there. Therefore, following a tutorial on how to create one is an option as well.
Let us know if you'd like more details on anything.
Great to see you here
Welcome and enjoy sharing yourself and reading others too!