Hi,
1. You can change that text here: https://i.imgur.com/84avGwN.png
2. The text can be changed as seen on the previous screenshot on point 1. You can also enable/disalbe the keyword suggestions.
3. By default the feature is to be used to export existing synonyms and then import, but you can also use a CSV file structured like this:
word1,synonym11,synonym12,synonym13
word2,synonym21,synonym22,synonym23The first word is the original, the rest are the synonyms for each line. Note, that you can’t use phrases from multiple words, each one has to be a single keyword.
4. I’m afraid that is not possible to check, the plugin does not keep track of the number of results in relation to the keywords.