Build a MSG box with Bootstrap 4, PSP, Javascript, CSS, HTML, Ajax and SQL

I want to build a message box in which it is possible to store the msgs in a database. These messages will be shown according to a date range and a subject filter (containing the "all" option as well). For each message, the name of the person who registered, their image, date and time of sending the message, and (if attached) the attachment must be shown. The box should display information about the database (total messages after applying the filter, total messages by subject, date of registration of the last message). When registering the msg, you should have the option to register an attachment along with the message text. The display of this attachment, if registered, must be through a modal activated on the paperclip icon that will appear next to the message (it will only appear if it has been registered). The attached word file contains images of the message box, database structure, box addresses (I used the "chat" template) and datapicker, as well as a draft (unfinished, whithout php code and with errors) that I started and may help to have a better view of what needs to be done.