There are several Flag props included with iClone that you could use. They can be found under Props>Physics Props>Softcloth Props
or in Props>Physics Props>Cloth Template_Grey, but the 2 available there need to be rotated Y -90.00 to get them in the correct position.
There are a whole bunch of parameters that can be changed in the Physics section of the Modify Panel to get the desired effect.
Gerry
System: Win 10 Pro (21H2), Asus X99-E WS, CPU i7-5930K -3,5 GHz, 32 GB DDR4 2666-16 RAM, NVidia GTX 1080 Ti GPU - 11 GB VRAM(Driver Studio-536.99), Samsung 850 Pro 512 GB SSD, 6 TB HD storage.