Please get the resource pack through ItemsAdder.
④ Unzip the downloaded compressed file, and overwrite the data folder inside to the data folder generated by the ItemsAdder file
⑤ Use the command /iazip to pack the material
⑥ Go to this path to get the resource pack ["plugins\ItemsAdder\output\generated.zip"]
⑦ Install the acquired resource pack generated.zip
⑧ Use command /ia to open ItemsAdder item list
⑨ Get the items! Have Fun!