Not being sure of the construction on your particular trailer, it usually comes down to "how to get the trailer high enough in front to drop the old jack down and out." If raising the front won't do it, you need a hole in the ground under each jack--I have read of several who have done this job and that is the hardest part: having enough room UNDER the jack to drop it straight down to clear the floor of the trailer.
The rest of it should be straigtforward mechanical work.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired