How to seal tents?

[Elek]

If I go with CO method in a tent, how can I seal it? I took a look at decathlon and all their tents have a ventilation system on the upper side that prevents a perfect air tight sealing
Moreover how can I deal with the heat made by the burning charcoal? Will it create a hole on the tent?

 

[Akeolodo]

Use regatta malawi 2 has been proven to work before, it's what i''m going to use