Answered: where to insert a second sim?

Hi. We do not have access to this same tablet model but this is how Dual SIM devices have their layout

1. The SIM slots may be stacked (one on top of the other) so that you may need to remove the one already installed to clearly see the two
2. They slots can be in an in-line layout which is hard to miss unless if the other one is a Micro-sized
3. The SIM slots can also be parallel on the side - also hard to miss unless if the other one is a Micro-sized while the already installed is Standard-sized.