If you look in the vanilla bedrock resource pack, you'll find a file named "blocks.json".
It's used to tell the game which groups of textures to use on which blocks (the groups can be found in "terrain_texture.json" but that's not important for this).
In it, you'll also see some blocks with an '"isotropic": true' setting or a longer version that specifies certain sides of the block. Changing those to false will stop it from randomizing the texture rotation.
Your pack's blocks.json file only needs to contain the changes you make so don't just copy paste all the ones you leave the same as the default.
It's used to tell the game which groups of textures to use on which blocks (the groups can be found in "terrain_texture.json" but that's not important for this).
In it, you'll also see some blocks with an '"isotropic": true' setting or a longer version that specifies certain sides of the block. Changing those to false will stop it from randomizing the texture rotation.
Your pack's blocks.json file only needs to contain the changes you make so don't just copy paste all the ones you leave the same as the default.