There is a portal above the base, and after entering, there is another portal. After entering, it is a venue, with the exchange of gas mines on the left, the bank on the right, the loan above and the deposit below. The dog can still be sold and returned to 1.
Because it takes three gas mines to open the crystal, the early mine is not enough, and keeping dogs is a very important economic source.
As for all kinds of situations, when to send troops, open mines and keep dogs, it is necessary to play more and accumulate experience.