Based on your question, it’s hard to exactly determine when you say:
…I add an image I can’t see it above the post title…
Also, considering that you said this is your first wordPress site, I am going to assume you added the in within your Post and not set it as a Featured Image which is what usually determines the image of the post on your homepage. Be sure to do the following:
- Open your post and on the right hand side, you should see a box label Featured Image
- Click Set featured image and choose or upload your image
- Update your post and you should see your featured image on the homepage
It should look like the following in your post: