Moto stop 2 years

Yamaha Xtz 750 Horete. Two years stopped.
I tried to start and ... he didn't want to.
The first step was to load the battery, which did not work.
The second step was to buy the battery, which almost resulted. The motorcycle started with difficulty, was half a minute in difficult start until it stopped.
I intend to:
-Cambiar spark plugs
-When I know how, clean the gas filter.
Any recommendation?
Greetings, thanks.