If you are certain that you won't shot more than 50 yards, then sight it in a little high (1 inch max) at 50 yards. That's the easy part. It is the adjustment part that can get tricky.

You don't say if the sights are adjustable. Most open sights are but there are some that aren't. If the rear sight is fully adjustable then you can move the impact up and down or right and left simply by adjusting the rear sight. Some rear sights are only adjustable for up and down and not right and left. if that is the case you need to tap either the front of rear sight one way or another depending on where you want the point of impact to move. This is often called "windage drift".

If the rear sight isn't adjustable and is fully fixed (common on many European rifles) then the only way to raise or lower the aimed point of impact is to either file the groove in the rear sight slightly deeper or to file down the height of the front sight. If this has to be done you want to be very, very careful because once the metal is removed it is gone forever. if you take too much metal off, then you've got some real problems. If the rear sight is fixed you would need to adjust "windage drift" in the manner stated above.

If you're serious about using this rifle as your main hunting rig I'd suggest scoping it or installing a good peep sight if don't like scopes.