how to increase bench press...

A powerlifting routine, posted here in the training forum.

but is your goal strength, or size? You train differently for both.
Heavy pressing exercises for the triceps was the key for me.

close grip and reverse grip bench are my favourites. you can also try rack lockouts.

work out where your weakest point of your bench is and master it
Work your back hard, lots of rows. I liked pin presses from just off the chest, paused benches, paused speed work on a second bench day during the week. If your goal is to get stronger you have to set up a program to get stronger, typically not looking like one out of flex mag. Basic progressive overload is very effective.
I Do Heavy Tricep Work...board Presses..we Use Bands Also...and A 3-2-1-1-3-2-1 Rep Program...

I Also Do Heavey Shoulder Work And Delt Work...