picking up and wearing armour

im making an rpg game but i dont know how i would pick up an object (armour) then it dissapear from the floor and apear in my inventory (which i dont have) and then be able to wear the object. i know this is probably very complicated and will require a lot of effort but please can anyone help me with any of this?

You have to break it down into much smaller steps and then figure out what each step requires. For example, if I were doing it, I would list out the following:

  1. create an object to be picked up.
  2. put a script on the object and in its OnTriggerEnter(), have it call a function on the player that identifies what item to add, and Destroy() itself.
  3. create a script on the player that holds the inventory in a list or an array. Add a function that, when called, checks the number that is input and add that number to the next slot in the list/array.
  4. As for wearable armor... that would require a much longer list just to work through (do I need to create separate torso meshes based on the armor shape, or will it just change the material on the player mesh? How do I match the number in the inventory with the specifics of the armor? etc.).

The thing is, if you try to do everything at once, you'll never get anywhere. Try separating what you want to do into much smaller steps (first this has to happen, then this) and think in terms of what the objects and scripts are doing, not what the player will see or think is happening.

Oh, and one last thing... you might want to start smaller. If you aren't comfortable with the basics of Unity and what it can do (and more importantly, how it does it!), you'll never be able to work out the harder stuff. Consider a simpler game first, then build on it. Which is better, a guy who runs a 5-mile marathon and finishes, or a guy who starts a 25-mile marathon and never reaches the end...?