Tensor network toy models have been invaluable in illustrating various aspects of the AdS/CFT correspondence. But can we construct more realistic tensor networks directly from a CFT and observe the emergence of a higher-dimensional bulk? In this talk, I will present a new step-by-step framework within CFT2 that constructs an exact CFT2 and at the same time AdS3 spacetime tensor network, using "BCFT Legos." I will illustrate this procedure with explicit examples that exhibit an emergent 3D quantum gravity dual and demonstrate how geometry naturally arises from the BCFT OPE algebra. A key ingredient in this construction is the recent development of generalized global symmetries, which enables a built-in, symmetry-preserving real-space RG flow. This naturally transforms the holographic tensor network into an exact MERA-like structure. Additionally, I will discuss the implications for the factorization puzzle and how this approach recovers essential features of earlier tensor network toy models describing wavefunctions on fixed time slices.