simplifying it slights, TAS is IAS corrected for numerous things (most importantly density).
If you line up on the runway with a steady 50 knot wind, your ASI will read 50 knots and your true airspeed (assuming standard atmosphere, sea level, no instrument errors etc) is also 50 knots. Your ground speed is TAS +- the wind coponent so you have 50KTAS - 50Kts wind speed which gives you 0 ground speed / you are not moving.
If you are struggling with why your TAS is increasing because of the wind, mayb try to think of it this way. You understand that TAS is your speed relative to the air mass you are in? so if the air mass is completely still and you are traveling at 50KIAS (assuming the same standards as before) you are doing 50Kts through this air mass. Now if you are not moving, and the air is moving at 50Kts straight at you, you are still moving at 50Kts RELATIVE to to this air mass.
I don't want to complicate things but if it helps (and you may already know it anyway);
I(ndicated)AS corrected for position/instrument error gives C(alibrated)AS corrected for compressability gives E(quivalent)AS corrected for density gives T(rue)AS