/give is a comments that gives you something in your inventory. This can also be done with /replaceitem, though /give is much easier. Let's go through the basics.

/give @p minecraft:deadbush 1 0
This command gives you a singular dead bush. Let's go through all the parts of this command.
/give: This is the command (duh).
@p: This targets the nearest player (in this case, you).
minecraft:: This is just the prefix to all minecraft items
deadbush: This is the ID for the dead bush (again, duh).
1: This specifies the amount. Here, you get one dead bush.
0: This specifies the data tag. This changes from 0 on things like colored wool and different types of wood.

So, to give myself a stack of Notch Apples, I would use /give @p minecraft:golden_apple 64 1

Hope this guide helped you at least start off with /give! :)