Need some advice.

[ClayPigeon]

Before even starting to make stories, I'd advice you to start mapping some rooms, houses and different environments from different categories(Outdoors, underground, caves, mountains, indoors, rooms, prisons and so on), to practice on your mapping and best it. (These maps won't be in your story)
I mean, just perfect your mapping skills, so they'll be good enough for your story.
Then, after your skills are good enough and you can map pretty well, and light rooms accordingly, you can start thinking of a plot for your story. Don't make it too childish or corny, but don't make it too dull or un-scaryish as well.
Make it interesting and worth playing and make it reasonable, everything that happens has a reason.
After you've thought about your story, you can start mapping for your story.

After finishing the first map, you need to start scripting it IF it has any events in it. (E.G: A monster appears, a sound plays, a key unlocks a door).

[Plank]

could someone help my with the new custom story im making

[Wank]

There will always be someone sticking with amnesia and not moving on to pigs. I would do both. I mean, machine for pigs is coming out in October.

[PutraenusAlivius]

There will always be someone sticking with amnesia and not moving on to pigs. I would do both. I mean, machine for pigs is coming out in October.

Who said that? A Machine for Pigs will release in Q2 which is April, May, and June.

[tezpull666]

I like your avatar! Scootaloo is the best pony! Also RD and AJ

[GiggleBlizzard]

Wether you should have the story made up before you start or not is all up to you, some people prefer to write a story and go strictly with it - others prefer to come up with a few ideas and then link them together in a story you're coming up with as you're making the mod.