i am trying to make a website should get data from database and add new data to database

i already learned html and css and the half of javascript, with these languages i coded a cool mainpage,working and outputing text editor and not working login-signup page. after all these information i need a database editor tech to get the text that users wrote then add it to database and get data from database then write it to the page will text show theirselves.picture of mainpage

the picture of text editor and output