The 0MB means it has no Data left to Download (Since you just insterted them by yourself in 5. And the thing with Choos HD Assets comes after every major Update with new Resources. It means that the Game has no Memory of beeing run before so it starts the normal Installation Proccess and realizes it already has all Files. The Number 7 has to do with the Memory or Checklist i mentioned earlier. When you have installed 7zip you then Rightclick the File and should find an entry called 7zip in the Context menu.

Just do a quick goofle search and you should find a downloadlink for the software. To unpack the data you nee md the free software 7zip.

i put an 'x' before Honkai to better recognize it later. Even though it should not break anything i would recommend just renaming the Registry Folder so that you can reverse any changes that might make it worse afterwards. By delete Honkai impact 3 he means the Registry Key (you are essentially editing the Memory list of the System so that it forgets what it has done in the past).

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