Installing JqueryUI and calling correct links in HTML page.

Installing JqueryUI and calling correct links in HTML page.

Hi all,
I just recent caught the Jquery and UI bud and would like to learn more about it. Therefore, I'm a real newbie and i require some assistance please in installing and linking the UI in my html page.
After downloading the custom UI  jquery-ui-1.11.4.custom, i see the following files and folder.

    --JQUERY-UI-1.11.4.CUSTOM  (Folder)
        --jquery-ui.css
        --jquery-ui.js
        --jquery-ui.min.css
        --jquery-ui.min.js
        --jquery-ui.structure.css
        --jquery-ui.structure.min.css
        --jquery-ui.theme.css
        --jquery-ui.theme.min.css
        --EXTERNAL  (Folder)
            --JQUERY  (Folder)
                --Jquery.js
        --IMAGES    (Folder)
            --*.png files

I'm not entirely sure which files i need to link and  write, in the head section of my HTML page.

To boot my folder structure is the following:
    --PROJECT  (Root Folder)
        --Index.html
        -- CSS
            --jquery-ui.css                   (I copied it here from the location mentioned above.)
            --jquery-ui.min.css               (I copied it here from the location mentioned above.)
            --jquery-ui.structure.css         (I copied it here from the location mentioned above.)
            --jquery-ui.structure.min.css     (I copied it here from the location mentioned above.)
            --jquery-ui.theme.css             (I copied it here from the location mentioned above.)
            --jquery-ui.theme.min.css         (I copied it here from the location mentioned above.)
        --IMG
                  -- .png files (I copied it here from the images folder mentioned above.)
        --JS
                  jquery-1.11.2.min.js
                  jquery-ui.min.js
                 
I went into the .CSS files and replaced the data or URL location from images to IMG.
eg. url("image/ui-bg_highlight... to url("IMG/ui-bg_highlight...

So basically my questions are.
1. What do I do with the Jquery.js file in the EXTERNAL mentioned above?
2. By copying the png files to the IMG folder and renaming the location in the CSS files, will this cause any issues?
3. What files do I link in my HTML index.html page and what exactly do i write?

I would really appreciate if someone can assist me on this.
Thank you in advance.