Advice for newbie

I am a seasoned veteran playing my first gig with an iPad. The band leader suggests Musescore to download his pdf sheet music onto the iPad making accessing the tunes easier and even allowing me to make last minute changes in the page order, etc.

Do I need to get the free version? Do I need to get Musescore on my desktop or laptop first and then access it with the iPad?

Any help will be appreciated.