Unbalanced iron condors are only slightly different than a regular (or balanced iron condor). These strategies are best used when you want to be slightly directional in your setup but also want the ability to profit if the stock remains range bound.
To build these condors and create skew to one side you would just need to widen out your strikes on the other side of the trade. Take your time with understanding skew.
For example, a stock is trading at $50 and you wanted to skew your strategy towards the bullish side you would widen out your strikes on the put side. Maybe instead of selling the $45/44 puts you sell the $45/40 puts. This creates more risk on the lower side of the trade therefore removing risk on the top side (bullish skew).
You would do the opposite of the above to get bearish skew, widening out your call strikes.