I assume it's a 790, right? If so it would be a bit different than mine but similar enough to tell you basically what must happen. There are nipples on each carb that are hosed to the evap system and those hoses get $hitcanned and the nipples capped. There is a hose to the right manifold (right on mine, may be left on yours) that also goes and gets capped. The tank breather i believe can be left alone since in now is just hanging open ended with the cannisters off. (tho it has that tipover valve in it)
The important part is the float bowl vent. There is a T fitting on a tube that connects the carbs. in the moiddle of it is a T joint where it connects to a hose. That hose must NOT be plugged. If it is the float bowls will overflow. With the EVAP system in place (on mine at least) the hose goes to a valve which opens when the key is turned on. The other side of the valve is wide open to the atmosphere. So with the bike on it's just the same as having a hose hanging down open ended. So just make sure theres a hose on the T fitting hanging down to below the bike. If you wish you can put some breather material in it to keep debris out of it. By the way, the "float bowl vent tube" is NOT connected physically to the float bowls, tho i'm sure you realize that having jetted these bikes in the past. It does vent the bowls, but via a passage where it connects to the carbs that goes to the bowls. Just wanted to mention that because one person thought i meant it was physically connected to the bowls.