In this sentence, "going" acts as the object of the preposition "about". A verb ending in "-ing" that functions as a noun is called a gerund.

১. A participle would act as an adjective (e.g., "a running boy").
২. An infinitive uses the "to + verb" form.
৩. Prepositions are almost always followed by a gerund rather than an infinitive.

অতিরিক্ত তথ্য: Gerunds are often called "verbal nouns" because they combine the features of a verb and a noun.