I've been using the RPG Maker series since version 2000. I could help a lot with it if you ask. I'll try to help what you've asked of now.
1. Switches
Switches are just variables with only 2 possible definitions. If you don't know what that means, think of a light switch. It can only go up and down, on and off. This makes things very defined and specific, causing you much discomfort when wanting too broaden the aspects of things such as NPC speech. To say it plainly, don't use switches unless you really need to. If you want to use them for things like chests do something like:
Make an event of a chest.
Define the name of the switch as something like "Chest001".
When the character opens the chest, turn the switch on.
Make a page in the event with the requirement of the switch "Chest001" being ON.
Use that page to define what happens when the chest is empty or open.
There you go, player opens chest, gets something and when he checks the chest again, the chest can be empty.
2.a password thing
As in the game asking for a password? This is a little harder with RPG Maker 2003. You can only ask for sets of numbers using an event command. Sorry, I don't remember the name of the command. You can use the command to ask for the input of some numbers and it places those numbers in a specific variable. Then create a Conditional Loop checking if the saved variable matches a certain number and if it does, they get in. If it doesn't, they get yelled at.
3. More sprites if available
There are many, many websites with resources for the RPG Makers. Try using google.
Hope I helped and/or can help further.
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