After that, right-click on 0 NiNode (above it) and select Block then Paste Branch (you can now remove the original NiStringExtraData, just right-click it and select Block then Remove). Once that's done, you'll find NiStringExtraData on the Block List (left side), right-click on it and select Block then Copy Branch.

You'll notice on that there'll be the model of the body you loaded on the right side of the screen, right-click the body and select Block, Insert, Nis., and NiStringExtraData (not NiStringsExtraData). Then I got NifSkope and loaded my femalebody_0.nif. So here's what I did, firstly, I installed this mod and got it successfully working (I assume you did too). If you haven't been able to properly implement the HDT physics on your character's body, then I suggest you check out the guide provided by Rebel47 on the post directly below! Provided you have installed the required mods (XP32 MSE, SKSE, HDT-PE, a compatible body, as well as the Sexy Idle Animation to test the collisions), proceed to the next step. There might be more but I believe that's all. Here are the related mods I have installed (in no particular order):

Not sure if it's 100% working myself, but so far it's good. I don't know much myself, but I got collisions working after doing some more steps.

Hdt physics extension brodual