There are a number of approaches to do it.
Like obtaining the Betreibungsamt to suspend or get an inventory of the assets. They are not let to move away what is visible.
While getting that done, most are on the second level. Normally you are supposed to send to pay you. With a single in registered letter form - that in 10 days you can proceed to formally contact the Betreibungsamt to get them to pay or to go bankrupt.
Call here,
Betreibungsamt der Stadt Zug
Fischmarkt 1
Postfach
6301 Zug/ZG
004141 728 31 35
Ask them whether Tradex is currently on their list resulting in Bankruptcy. If it is, ask them how you can get in to the list of lenders. If it is not, ask them. If they are still in business, they will try to pay you before the betreibungsamt will proceed to close down them.
Once you are in the list of lenders, there's nothing except to wait.