Humu, let's see if I can explain in a acceptable way: Firstly, click on the "down" arrow on the right of the "Edit profile" button on your profile, and then click on "Classic editor"; This is the code you'll use:
Just copy and paste it on the classic editor and replace the "X"s for the values you want. Most of the sections are probably obvious, but just for completation's sake: name= Unit's name; Level= Unit's level; rank= CC, AW, AW2, AW2v1 or AW2v2 (if the unit is not CC'd yet, you can just erase the "rank" section); skill= Unit's Skill Level; cr= Unit's Cost Reduction; To add more units, just copy the second line and paste it right below of itself, but always above that third line (since it ends the list). Also, on my profile there's just Blacks and Platinums, but you can add any rarity (I myself will add the others on my profile in the future... at least the Golds)
That's about it, as you can see, this little guide(?) is just for the list, if you want to hide them as well, just ask and I'll try to help.
PS: I don't know if it was a good explanation, so if it wasn't, you may want to ask Kkentauro, since they are the creator of this code. See also: Code's thread
I'm just assuming you also want the "Black" image on top, but if you don't, just remove the middle line from the top list code. Also, to do the Platinum (and other rarities) one, just reclace the "Black" for "Platinum" at that same middle line.