As far as I understand, here are the steps to be taken. 1. Obtain a "numéro identification d'entreprise". See [here](https://www.bfs.admin.ch/bfs/fr/home/registres/registre-entreprises/numero-identification-entreprises.assetdetail.241588.html). 2. Register to [Caisse Cantonale Vaudoise](https://www.caisseavsvaud.ch/entreprises/cotisations/employeurs/ ). Fill [this document](https://www.caisseavsvaud.ch/fileadmin/user_upload/form_affiliation_employeurs.pdf). 3. [LPP](https://www.bsv.admin.ch/bsv/fr/home/assurances-sociales/bv/grundlagen-und-gesetze/grundlagen/sinn-und-zweck.html) and [LAA](https://www.kmu.admin.ch/kmu/fr/home/savoir-pratique/personnel/gestion-personnel/obligations-employeur/assurances-sociales/assurance-accidents-laa-aanp.html). 4. Taxation [at the source](https://www.vd.ch/themes/etat-droit-finances/impots/pour-les-employeurs/impot-a-la-source/) (looks like the Caisse Cantonale Vaudoise might offer this already).