Im actually really new to this, im setting up a gamebook because I find it a bit easier but I want to know if I could add some sort of inventory system so that players could use it in a turn based scenario combat (I think im doing too much for a newbie ._.) and puzzles and such.

In a gamebook, you probably don't need an "inventory system".

You can have a group of flags called things like "has hammer", or "has sword".

Then one of your combat pages might be a "script and text" page, with the script including:

if (GetBoolean (game, "has hammer")) {
  AddPageLink (this, page98, "Hit him with your hammer")
}
else {
  RemovePageLink (this, page98)
}

Which adds a link from the current page to page 98, the option only appearing if the player has a hammer.

If you want to do things more complex than this, then you should probably try making a text adventure that looks like a gamebook instead.