Migrating a wordpress site from http to https

Server has a SSL cert set up for the site
Website is live
We assumed it would be straight forward but after messing things up realised it needs a pro.

The database is accessed via your control panel or we can give you access to our online PHPMyAdmin where the website URL will need resetting.
We have currently over ridden the URL in wp_config file

Once that is done the htaccess file will need sorting out to redirect from http to https

Not sure if we have the experience level correct?

Thanks in advance

Contact number 07929 121347 rich