As a non-EU national studying here you cannot be self employed nor can you work for the first 6 months of your course. You need an employment contract with a Swiss employer and you cannot work more than 15 hours a week during term time.
I don't know where you're studying, but this is from the ETHZ website: Gainful employment Main content
During the semester, you may accept a paid part-time job of no more than 15 hours a week. Full-time employment is permitted during the regular semester vacations. However, in both cases your employer will have to apply for your work permit at the cantonal Office for Economy and Labour ("Amt für Wirtschaft und Arbeit" – AWA) if you come from a non-EU country or from Romania or Bulgaria. This is only possible once you have received your residence permit! Important:
Bachelor students from non-EU countries must have lived in Switzerland for at least 6 months to obtain a work permit.
During their first 6 months in Switzerland, Master students from non-EU countries can only obtain a work permit for a job at their ETH department.
Further information can be found at: www.arbeitsbewilligungen.zh.ch