I've not used a Mikrotik for this, but from the RUT side it should be pretty straightforward:
- Set up a WiFi AP on Mikrotik.
- Login to RUT950's WebUI and go to the Network → WAN page.
- Select WiFi as your main/failover WAN and save changes.
- Then click the 'Scan' button next to the WiFi interface in the same page and locate the Mikrotik AP from the list.
Info on this setup can be found here.
RUT950 does not support 5 GHz WiFi, only 2.4 GHz.