If we want to use a verb after a preposition, it must be a gerund. It is impossible to use an infinitive after a preposition. So for example, we say:
I will call you after arriving at the office.
Please have a drink before leaving.
I am looking forward to meeting you.
Do you object to working late?
Tara always dreams about going on holiday.
Gerunds function as nouns
Verb + Preposition + Gerund
There are a lot of verbs with preposition can be followed by gerund. Here are the verbs and their prepositions.
1. succeed in
2. dream of
3. Have you succeeded in finding a good job?
4. I always dream of being rich.
Adjective + preposition + gerund
1. I'm interested in working for you.
2. She's very good at singing slow songs.