Problems Parenting Armature Scales and Deforms My Mesh

I’m very new to blender, I have been playing around trying to rig mesh to a skeleton for animation, It is a pre-made skeleton for use in a game. I have to either scale the mesh or the skeleton to fit them together. My problem is whenever I eventually line them up and parent them to armature, The Mesh returns to its original size, and is no longer aligned with the skeleton, It also deforms and twists. Is this a common problem with an easy fix? I’m not sure how much more information I should provide. I have been searching for answers but I’m not sure to be searching for, no idea whats causing this to happen. Thanks in advance

You should be able to scale either the mesh or the armature in object mode, and then make sure you press ctrl + a and apply the scale. This will make it so the mesh or skeleton keeps the same size but the scale returns to 1,1,1.

You may also want to apply the rotation if you’ve had to rotate one of them to match the other.