Dextrose is glucose monohidrate, very "fast" sugar.
After your wo you need to replenish your epatic and muscular glycogen mainly used as energy doring wo.
If you use some dextrose in your post wo supplementation this will be very helpful for this purpose.
In my post workout drink I use about 30 g of dextrose and 5 g of fructose together with whey protein and creatine. It works.
Many would use some more than 30 g, but you must be careful about your bf...

In what form do you take dextrose???

Dextrose is sold as "dextrose", bro.

its in powder form at any bulk food store, brewery, online, etc. also look for the name "cornsugar" (same thing diff name)