You can't upload a video's to Nostr. You upload them on a server somewhere. Nostr.build is build into most clients. But i recommend you guys to self-host your video's. That way you are in control.

There are several options to upload videos: - https://nostr.build (limited to 20MB? maybe more now?) - https://satellite.earth/cdn (unlimted size, pay with sats) - https://files.v0l.io/ (free, unlimited?) - https://nostrcheck.me/

I use my own hosting website and direct nostr to your website or paste the link. The same method applied to any hosting platform like nostr.build