I tranfered my HostGator domain to opalstack and now trying to update my website can you please help
Assuming you've transferred the data already to the server you will want to do the following.
Create a new PHP type app in the Opalstack dashboard.
Add your domain and configure the DNS as well. (Note that using our name servers will impact your email, so you will need to configure that too if you use them and have email currently on your domain.)
Move your site data into that new app directory using sFTP/SSH.
Create a Maria database and import your old servers MySQL database into it.
Assign that app and domain to a new site.
Finally, edit your sites 'wp-config.php' file with the new database details over sFTP/SSH with your desired text editor.
Then your site basically should be setup on servers and accessible via the internet. Feel free to let us know if you have any further questions. You may also open a support ticket if you wish.