Hi and welcome to Hive.
You should have a button on your profile to write a post. Depends on what User interface you are using.
On Peakd it will be on your banner.
On Hive.blog there is a little pen next to your avatar.
I have delegated some Recourse Credits to you so you should be able to post. You will need to power up some Hive to be able to post and comment freely in the future.
Remember to post ONLY your own original content. If you copy something from the internet, it has to be clearly sourced or it might be considered plagiarism.
If you told me in which community or what kind of #tag to use in my introductory post
Use
#introcuceyourelftag. And you can post just on your blog, or choose the one that will fit to your introduction. Check the community guidelines before your publish.