Recently we changed the supplier for our telephone system. The old system was good, but simply too expensive. Our new system is much cheaper, but very difficult to use. It’s been installed at our office for two weeks and I still can’t make head or tail of it (werde nicht schlau.)
The idiom comes from the name of the two sides of a coin in English. On one side is the „head“ and so the opposite side is called the „tail“ (no matter what picture is show on the coin). For example, if you toss a coin to help you make a decision, while the coin is in the air, you call either „heads“ or „tails“. So the idiom „can’t make head or tail of it“ means that something is unclear and confusing no matter what side you look at it from.