just dry the TLC plates

KEDDE REAGENT A

Dissolve 3,5-dinitrobenzoic acid (2 g) in 90% ethanol 100 ml).

KEDDE REAGENTB

Dissolve sodium hydroxide (5 g) in distilled water 100 ml)

Drying and heating both are nontechnical words for each other and are same.

Drying is lost of solvent while heating do same works.

As per thermodynamic on every 10 degree celsius of temp rising doubles the rate of reaction.

But main thing which is important is that it should not touch to nondestructive temperature (reagent/ analyte)