Adding Fatburners?

Hi Guys, hope all is good

Just a quick question, when is the best time to add in a fatburner (pref HEAT)?
See i just started dieting and training again after my dieting and training took a dip due to studies.

So im gonna start a old diet that i have.

Can i start it when i start the diet? Or....
Am i right by saying i should wait 2-4 weeks before ading them in? Then once im properly into the diet then i can add em?

Need to get back into the game!!

Tx

Rather check how it goes without the fatburners for 2-3 weeks or so just to check how your body responds to the new diet. Bring it in at a later stage when cardio and diet has been solid. Hope it goes well