This is a full controller aided approach. (which I think might be quite difficult in FG but im willing to give it a go). Normally flown in bad weather or when no ils is available the controller will give small heading changes the whole way down the approach path (possibly as small as 2/3 degrees at a time).
Simultaneously you'll also be told when to begin your descent to intercept the proper glide path. At half mile intervals the controller will read out the height you should be at when passing that range. Although the controller can see where you are laterally in relation to slightly left or right of the centreline there is nothing to show exactly where you are vertically. So its the pilots responsibility to try and match the heights given and make adjustments as necessary.
Thankfully the heights are fairly simple. A 3 degree glidepath equates to 300ft for every 1nm. So a chart like the one below is what is used.