@Selena Stew
In the situation described, you'll have two separate contracts. One with the seller of the property, and one with the buyer.
With the seller, you'll have P&S contract between the seller, and you. In this case you'll be the contract vendee rather than as the buyer, as normally would be the case. As to terms and conditions, you'll negotiate the various conditions you normally would with a seller, such as earnest money amount, closing dates, due diligence dates and any other special conditions.
Most real estate attorney have addendums to standard P&S contracts, namely, the contract is not assignable, and is the first item on their addendum, otherwise standard contracts is assignable by default. Make sure the seller allows you to do a number of assignments in case the first one or two falls through. I don't usually wholesale, but one seller has in his contract that this contract is assignable only once, and additional assignments require further approval.
When you find the buyer, you'll have another P&S contract prepared, in this case the seller is you, not a owner of the property, but as the contract vendor, and the buyer. Here you'll have to set your conditions similar to the one with the seller, earnest money, due diligence dates, etc., that mirrors the one on the seller side.
What I described above is the simple frame work of contracts involved in doing a wholesale deal, where the seller and buyer is on separate contracts, neither is aware of the profits you're making. Your profit is simply the difference between what you purchased the property from the seller, say $35K, and what you sold it to in the buyer contract, say $40K. And this is what they do in my area, in your area, could be different.