How often should I bench press to gain a lot of muscles to my chest?

Because muscle building is BIOLOGICAL, and not magical.

Muscle gain is TRIGGERED by hard training.

But that extra muscle isn't built WHILE you train. New muscle is added AFTERWARDS. This process is called 'recovery'.

The harder you train, the more 'recovery' you need. If you train again before your recovery is complete, you will interrupt the process.

So if you train a muscle hard enough to stimulate plenty of muscle-building, and then train it again the next day, and the next, and the next, it will never have TIME to build the extra mass you keep 'telling' it to build.

Pushups.