I'm doing a few calculations to understand how to go from the Earth to the Moon. I used an elliptical (Hohmann Transfer) orbit to go from LEO to a circular Moon's orbit performing two $\Delta v$ (resulting in $\Delta v$ ~ 3.94 km/s). I don't know exactly how to perform the landing process and calculate the required $\Delta v$. I few papers in the literature show that it is between 1.5 km/s - 2 km/s. I think I should use an hyperbolic orbit but I'm not sure how. Any clues for a simple calculation? also, does it depend on the altitude above the Moon's surface?