gerund/infinitive

[moqaddas]

peace be upon you,
what are gerund and infinitive?Sometimes i feel difficulty to differentiate between them i.e.
To read this novel is difficult.
(or)

Reading this novel is difficult.

What is right to say?

[allenman]

peace be upon you,
what are gerund and infinitive?Sometimes i feel difficulty to differentiate between them i.e.
To read this novel is difficult.
(or)

Reading this novel is difficult.

What is right to say?

Reading this novel is difficult -- yes, no issues.

To read this novel is difficult -- no, sounds wrong to my ear.

Understand this is my opinion -- the "to read" form may sound correct to other natives. I would like to hear other replies as well.

Not a teacher