You can either use a paint stripper to take the paint and sealant off. Then work an emulsion onto the bare wood. Or you can use a heatgun to take the lot off and then start again.
It depends on the size of the item and the stuff that's on it.
Strip of the paint, use a mild solvent to remove some of the stain. Buy wood sealer and seal the wood. Then paint.
You are going to need a coat of sealer first. Kilz works good.
