PHP script modifications

I need a modification of the php script. Namely, I have a website that deals with the translation of subtitles: [login to view URL] As you can see the process is as follows: 1. upload subtitle 2. select language 3. Click the "auto translate" button 4. the subtitle text is scrolled automatically and translated 5. download subtitle THE TASK: now I need the following modification: 1. upload subtitle, the original subtitle will be displayed in the table under the column "Original text" 2. if the "Download file" or "Auto translate" button is pressed before "Select Language" to display a pop-up error: Please select the language first 3. when the desired language is selected for translation via google widget, and pressed the "auto-translate" button, to translate that subtitle text in the background (while translating the subtitle text in the background and if translating for more than 5 seconds to use the Bootstrap button Loading all until the subtitle text is translated , this button: [login to view URL]) and when the background translation is done, to display that translated subtitle text in table column "Translated text" Arranged EXACTLY in the rows/columns as the Original text is. 4. Download subtitle stay the same supported subtitle files must be stayed the same for translation, we accept srt, sbv, sub, stl, vtt and ass.