I do LCD refurbishing and the 6S plus is not a phone you want to learn on. To answer your question directly, to do the repair you will need:
A glass separator. These heat up the display to soften the glue that holds the display down and run a wire between the glass and the LCD.
A polarizer/OCA removal machine. Looks like a little guillotine with a blade that heats up. The blade cuts under the polarizer (from here on out POL) and scrapes the POL and OCA off.
Chemicals to remove the OCA. There are many out there and most of them will stink you out of your house.
A POL/OCA laminating machine. You reapply the POL and then then OCA.
A POL/OCA press. This heats up and then presses the glass, OCA and POL to form a tight bond.
An autoclave. This removes the bubbles from the screen.
A framing machine. This applies the frame that keeps your screen held onto the base of your phone.
You will also need OEM glass, POL, OCA, silver conductive epoxy, camera bracket, earpiece mesh, prox sensor bracket and a spare backlight just in case.
Success rate on the S series is pretty low. The LCD itself is only .038" thick and breaks a ton. There isn't a supportive backing like the 5 series LCDs.
Also, please don't use LOCA on your phone. It is not a good solution and I run away from any repair shops that offer LOCA without rebuilding the display.