Soldering a 24pin SMD IC. The base is soldered to the board. How do I do this?

[frascati]

Pretty new to building with SMD.

All the tutorials I've watched on youtube place the IC and solder the pins to the lands.

I'm replacing a 24pin IC and after removing it I discover that it's bottom is a large solder pad that is soldered to the board's ground.

I have not seen mention of this in any tutorials.
How Is one supposed to make this solder flow if you cannot actually see it happening?

 

[CocaCola]

Reflow oven or hot air heat gun.... As for knowing when, you can tap the chip with a pair of tweezers and observe it or simply watch it settle into place...

Since you have holes in the thermal pad you can try this technique...

 

[frascati]

Coca Cola thank you very very much for that link.

Chip is in, up, and running fine!