PHP modifying question

Ok, I made some forums of a rock band at Proboards.
After 20 days of existence, some dude came and told me "Hey, I can host you a phpBB2 forum for free! What do you say?" and then, after discussing with 2 of my mods, I accepted the offer.
The new forums are very good, I like them a lot, but I need to know something. I got Admin priviledges, but I cannot modify the website, like for pasting codes into it in order to have a shoutbox, chat room, mp3 player, etc etc.
How can I do that... I can't keep asking this guy to modify the forums each time it is needed (every 20 min ), besides, he's not available in most of the time.
He told me that I needed to know basic PHP and needed to have the files of the forum...
What do I have to ask him for if I'd like to paste some scripts???

Old Forums
New Forums
(They're both in Spanish)

Doomulation said:

You need to have access to the web server where the files of the forum are stored and you do of couse need the knowledge to modify and write new PHP code. That's all.

Click to expand...

Uhh..
Yeah I tried to learn about PHP but ... it's too confusing, I understand nothing
Could the files be transfered via FTP?

But it's like... Here's a mod... follow the instructions:
1. Unzip
2. Copy shoutbox.php to root/
3. Your done!!!

So, I guess that I could just copy the file given to where it says and period, the mod should be ready...