thanks for all the info do you guys think i can use the sand and the aragonite i have in the tank if i clean it ind put the laterite under and what about skimmers and water flow
Aragonite is going to skyrocket your pH very high. While there are certain freshwater aquarium setups that like high pH, in general that is not a very good mix if you want a heavily-planted tank. Once you start getting in to pH's in the ~ 8 range, the list of plants you can successfully grow starts shrinking pretty rapidly.
If you have regular sand in there already, yes the regular sand could be used in a FW planted tank. If it is "live sand," then no, as once all the living things in it are exposed to freshwater they will die, decompose, and lead to one heck of an ammonia spike.
Speaking of things dying, also keep in mind that the saltwater bacteria in your filter currently are not going to survive the transition to freshwater (unless you transitioned very very slowly over the course of several months, from saltwater to strong brackish to weak brackish to fresh), so if you just switch over immediately to fresh you are going to have to re-cycle the tank.
If you are independently wealthy (like, Donald Trump's grand-nephew or something) then the ideal substrate would be a specialized planted tank substrate: Eco-Complete, Flourite, Flora-max, etc. But you would probably be looking at $250-400 worth of substrate. By comparison, to put down a thin layer of laterite and then use pool filter sand, you would be looking at probably no more than $50-75. (Note: if you are going to use sand, pool filter sand is what you should use, not child's play sand. Pool filter sand is larger grained, so it is a little better at hold down plant roots and also won't get kicked up and cloud your water nearly as much as a finer sand will. You can buy it, not so surprisingly, at any place that sells pools and pool supplies. Usually runs about $7-8 per 50 pound bag.)
Laterite is a natural clay that provides nutrients, especially iron, to plant roots. It comes in a box and is roughly the size (usually) of small aquarium gravel. You would put it down first...sprinkle it on the bottom glass of the empty tank. You don't even need to "cover" the glass completely, just sort of thinly sprinkle it so there is a single layer of it on the glass, where you can see through it. That's all it takes. Then pile on the rest of your substrate over the top of that.
If you have a lot of time, space, and patience, then
making mineralized soil and putting a layer of that below the sand will work wonders. It's certainly not necessary, and the process is not for the faint of heart, but people who have done it rave about the results.
There is no need for skimmers in a freshwater tank.
As for flow, in all likelihood controlling the direction and strength of the flow will be a consideration more based on your fish than on your plants. It's true that some plants prefer areas with moderate flow, other plants prefer areas with minimal flow, but in general most plants are going to adapt reasonably well to whatever conditions are present in that regard.