Start with a recurve. The riser is similar to the riser you are used to on a compound. The form is also closer to that of a compound, except for the higher wrist and the anchor. You can work your way backwards to a longbow. Longbow requires a few more adjustments.
Start by using a recurve target sight. It only has an aperture, not a scope. Once you are comfortable with that, you can go barebow, then move into the longbow. If your goal is longbow, then shoot the recurve with the index finger anchored in the corner of your mouth. If you plan to stay with the recurve, you should anchor just under your chin with the string coming right down the center of your face.