How to write a web gallery with an admin panel?

Question

Gallery

Welcome all! Himself a novice developer, a beginner in the sense that he has not yet created his own project, but I have some knowledge. Here I want to create my own website, which will have my portfolio with the ability to manage photos through the admin panel. The admin panel should perform not only standard actions (deleting-adding photos), but also the ability to post content (that is, part of the selected work, anywhere on the site, and not just in the portfolio). It works as follows. We open the admin panel, follow the portfolio link, all photos from the portfolio are displayed there (for example, a beautiful picture with the signature my site-:), which leads to the demo of my site.) You can also add or remove one or more pictures. We can select the pictures, sort their order and plop where necessary, for example, in the article "how I spent the summer." And then they will be displayed both in the portfolio (on the portfolio page) and in the article. You can turn off the option - only in the article or only in the portfolio. Sorting from the pages of the site, the user on the site can choose what he wants to see, for example, my scripts, in this case, written links to the store :) are hidden.
Question 1.
Where to display all pictures in the admin panel for selection? Is it a form?
Question 2. On what would you write such a sorting, as I need and an approximate algorithm?
Question 3. I don’t know how to write demos (well, to show my brainchildren in action, so to speak) - I can roughly imagine how, but maybe there is a ready-made solution, peep and do something like that? :-) Thank you in advance for your answer