Help with dual monitoring

I am not too sure if this is the place to put this, but I have been thinking of dual monitoring for a while now but I am not too clued up about it.

I currently have the LG Ultrawide monitor (34UC98) which the resolution is 3440 x 1440.

I am looking to add the 4K LG monitor (27UD69P) and the resolution for this monitor is 3840 x 2160.

Not sure if this is relevant but these are my computer specs: Intel i5 7600k 3.8GHz, 24GB Corsair DDR4 3000Mhz RAM, 1070 8GB Turbo Asus, Asus Prime Z270-A Motherboard,

Is there anything I should know before doing this? I have done a bit of research myself but I will be honest, I came out more confused than informed. Would there be an issue with the monitors being different resolutions, would it require one or the other to be downscaled etc...

A little bit of what I do on my system is gaming, photography post production & graphic design (using Adobe Suite).

Anything tips or information on this would be much appreciated!