You need a gunsmith.
line up the target on the top of the front sight while sighting the front sight through the rear peep sight.
Aligning front and rear sites to aim
1. Remove the screw to the rear of the front sight ramp.2. Remove the "blade" from the front sight ramp.3. Remove the screw from the front of the front sight ramp (which was formerly seated under the "blade").
The front and rear sight
Savage firearms bought Stevens in 1920. Brownells can also supply a generic front sight.
Would the front sight hood for what be compatible with a G98/40, which by the way, is not a Mauser. The standard K98 sight hood will fit on a G98/40 rifle, but it will not sit well and would not be correct. The 98/40 used a proprietary sight hood that no other rifle in the world used. They are exceptionally rare today.
You are looking for the "sight picture". that is formed when you align the rear sight with the front sight and the target. Here is how to find it. At the very end of the barrel on top is the front sight. About 2/3 of the way back and still on top is the rear sight. If you hold the rifle stock to your shoulder and support the front of the weapon with one hand you can look down the barrel. You will notice the rear sight looks something like a V and the front sight will look like a dot. If you move the rifle so that the dot appears to be in the middle of that V you have accomplished your initial "sight picture". Now keeping the dot in the center of the V align that with the target you wish to hit. This is your complete sight picture. It will take practice to figure out if the wind is affecting you and distance to the target and a lot of other things but that is the correct way to sight the rifle in and should get you started. Good luck.
Try e-gunparts.com
The rear sight must move in the direction you want the point of impact to move. The front sight can be moved in the opposite direction.
Crosman still has parts for this rifle. contact Crosman at the link below (Customer service) and order the parts you need.
Blade type mounted on a dovetail cut in the barrel