In case, you have made any changes on the code, css or js file. Backup them first so you don't lose your work. Download them or take a note what you have changed.
.env ( you can also do it via the env editor in your admin panel )
public/uploads ( you can zip it and move it somewhere )
Download the code from CodeCanyon and directly upload it on your hosting, in the same place where your existing site is.
Extract the zip files. Overwriting old files.
You old .env file contains previous settings to connect to db, mail and so on. So it is required to but it back.
Here, if there are migrations for the database to be done, will be run. If there is nothing to be done you will get 404 site.