Hola Mike

In Spanish we always call "gerundio" to the form -ando, -iendo ( -ing form in English, as present participle or gerund) 

Some structures are different in Spanish and English and this is one of them. To say before and after doing something, in Spanish we use antes de + infinitive and después de + infinitive (never the -ando/ -iendo form) - if it helps to remember, you must know that after any preposition in Spanish we cannot use the -ando, -iendo form, only the infinitive (-ar, -er, -ir). 

Saludos

Inma