Once you have the NIE, you should apply for a digital certificate to be able to sign documents digitally in Spain (you will need it to sign your employment contract) and to carry out other administrative procedures electronically.

In your country of residence: you can apply for it at a Spanish Consulate.
In Spain: there are several places to apply for it. At the UV itself you can easily process it, both in the General Registry (by appointment) and in the auxiliary registers of the centres.