You will most likely need an allan key (sometimes called an allan wrench or a hex key - very inexpensive tool) to take out the HP port cover on your 1st stage.

You will then screw in the threaded end of the hose into the threaded port that is now open. Use an open end wrench or an adjustable wrench to tighten it down. It has to be snug, plus about 1/4 turn and you should be fine.

A packet of lube should be included for the o-ring unless it is pre lubed. If it is not, get some silicone grease at your dive shop and just a VERY VERY small coating on the o-ring.

If you need any additional info, please send photos and I will walk you though it step by step.