Unfortunately, at this point of time He Xuan is unable to cast protection charms, using a traditional way: a wand. It’s definitely not a first year level of knowledge and skills, but one day he will be there, as well as luckily He Xuan was able to engage Hagrid to buy used books, instead of new ones, which means there was some extra gold left, specially and officially allotted for this crazy shopping, to buy some extra literature – the former ghost was planning to study mostly in the school library and practice somewhere in secret – He Xuan was sure that this time with proper instructions what to do he will be able to perform better. Of course, but some essential keepers of knowledge are better to have on his own, in constant access. 