ahramin
Just a simple 3 x table, and the DME/ht checks on the approach plate. A 3-degree slope equates roughly to 330' per nm.
Desc rate is calculated from the groundspeed / rate of descent table, also on the app plate. If your ground speed is 120kt, ROD may be about 650' fpm. Lower ground speed due to head wind, ROD may be 550-600' fpm.
The idea is to get to MDA and the MAPt at the same time.