ᐅ Connecting the Electrical Distribution Board in a Construction Site Container

Hello from NRW, my name is Michael and I have the following question for the electricians among you: what is the best way to connect the fuse box shown in the attachment to the distribution board, or vice versa? My friend is a trained mechatronics technician and has all possible personal protective equipment, such as complete tools and gloves rated up to 15,000 volts, as well as a lot of experience connecting car Hi-Fi systems. The fuse box is located in a locked area inside a container, and we are planning to set up a garden shed there. The cable from the distribution board is already inside the container, and everything is, of course, protected by circuit breakers. What is most important to us is which fuse should be connected from above and which from below to get 230 V (no need for three-phase power), and an electrician is not available for less than $250 (that is about as much as we plan to spend on the whole shed). Is there an electrician here who can possibly advise which fuse to connect from which direction and preferably in which order? We are fully aware of all the dangers involved with high voltage and only use gloves certified by the electrical association. Therefore, we are only asking for a completely non-binding brief guide, and connection will only be made when there is no power (we have a suitable multimeter and everything protected). We only work on the fuse box when the power is off and only with appropriate tools and gloves, always checking three times with the multimeter. We are very grateful for any help and would be happy to thank you with a box of beer and anything else imaginable (even if the helper is not from NRW). Many thanks in advance and sunny greetings from the Ruhr area, Michael

PS: Of course, we did not connect the fuse box ourselves and do not know who made the previous faulty installation. We are both sure that it was not a professional, and we would never put it into operation that way because we are fully aware of the dangers.