There good to go out the box.
If your using the battery that came with the marker, have a spare ready at hand just incase. Fresh good quality battery is needed, or you could run into problems.
Dont screw the barrel in too tight, as this can put pressure on the eye pipe. For precaution, you can put an oring on the back of the barrel, this will stop the barrel from being screwed in too far, and will sit nice and tight.