If you would like to add a new coordinate system to Professional please follow the steps below;
Find the system you want on this site:
Once you find the one you want scroll down and click on "PROJ.4", it will display a line of information. Copy that line of information.
Open Professional and go to System>Coordinate Systems>New
You will then have this window:
add the CRS value, this will be the ESPG number. Example "EPSG:26919"
For the name add the name of the system you searched for. Example "NAD83 / UTM zone 19N"
In the Proj box add the PROJ.4 line of data you copied from the site.
Example:+proj=utm +zone=19 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
Also then tick the "is Active" option and save the changes.
The system will then be ready to use in a project.