Gerunds & Infinitives

A gerund is a noun made by adding -ing to a verb. Since it is a noun, it can be used as a subject, object, or as an object of a preposition.

An infinitive is a verb in the form that starts with 'to'. To swim, to play, to smell, and to eat are examples of infinitives. 
The simple form of the verb (without to) is used in dictionaries.

Compare the -ing form as a Gerund (used as a noun) and the present participle form used in the progressive tenses or as an adjective.

I am swimming right now - in a progressive tense

Swimming news is a great magazine - as an adjective.

Infinitives are usually placed after another verb.

He went to deliver the package.