Parameters enable you to add a data merge on to the end of a tag. Data will be merged into the Tag from your ESP at the time of send and be combined with the contextual rules you have set.
For example, it is possible to merge M for male gender and F for female gender and then display the selected image or widget.
When you select Parameter string from the condition selector you have two options:
Parameter name = the name of the parameter in the Tag, this is used for you to know what data is being merged. For example: gender
Parameter value = the exact mail merge command from your ESP. Post merge this is the value that tells the Tag what to display. For example ‘M’ or ‘F’.
Once you have select those values, you can build your rule as normal!