Well now afterwards you can see the "Edit" button on the bottom of your post, on the right of the amount of votes you have :)

By clicking it you can edit. There should be three "boxes" for text. First one is the title/header, second one is for photos and text and below this one you have one for tags. You can use 1-5 tags per post and if you want you can add a few which describe the post, helping others to find it :)

Edit: Ah, you already did. Good job!